Used Eht Sheet Metal Shear for sale (37,093)

Condition: good (used), FS Frank Schäffler Used Machines You are bidding on: a branded device – a press brake, from a very good and well-known manufacturer – Schechtl. Device features: Press brake Schechtl HA The beam bends cleanly – a test is possible. Degree indicator Bending length approximately 310 cm Sheet metal thickness up to 1.5 mm (steel, aluminum, zinc, etc.) Standard beam Dedpfx Alsz I Txws Ssku Foot closer Sheet metal support Optionally, a roller shear with a beam can be added; this would have to be ordered new from the factory. Price list from 2024 – net price – prices are now significantly higher. Important! Optionally, you can find and purchase many machines and machine accessories in our shop, such as various beams, depth stops, and everything else related to sheet metal and steel processing, including press brakes, plate shears, drilling machines, and round machines, as well as slitting and profiling machines – accessories (beading device, round rolls for gutter production, back gauge, etc.), and other hand tools and spare parts from many top manufacturers. I am always available to answer your questions. You will receive an invoice with VAT shown. Free loading is possible – weight approximately 2000 kg. Inspection and testing are possible and desirable after scheduling an appointment by telephone. Payment in cash upon collection. Take advantage of our experience and expertise; we will be happy to advise you. Collection by the buyer himself (or by a shipping company commissioned by the buyer) should take place within 10 days after the end of the auction. Location: 97249 Eisingen, approximately 3 minutes from the A3 and A81 highways. Article number: Press brake HA 310

Condition: new, Universal shear for cutting metal sheets. Includes base frame. Djdpfxega T Efj Al Ssku Working length: 1000 mm Sheet thickness: 1.5 mm Weight: 70 kg

Condition: excellent (used), functionality: fully functional, Year of construction: 2014, control type: CNC control, Equipment: CE marking, Used Cnc folder Ras XL Center 63.30 cnc folder up down folder 3metre For Sale Dkodpfx Aljym T Iao Sju Capacity: 126-inch / 3.2 metre (3,200 mm) folding length and can handle up to 16-gauge (1.5 mm) mild steel. Bi-directional Folding: The machine folds parts both up and down, which minimizes material handling by the operator and increases production speed. Precision Technology: It is equipped with five servo-regulated motors for high-speed operation and includes programmable gripper positions for creating tapered or conical parts. Software Control: Features a multi-touch PC control system where operators can draw profiles directly on the monitor; the software then automatically calculates the folding sequence and provides 2D/3D simulations. Design Flexibility: Offers 300 degrees of free space in front of the folding beams, allowing for the creation of complex part designs that standard machines might struggle to accommodate.

Condition: ready for operation (used), HAULICK slitting shear for rolled sheet metal / rotary knife shear -Max. sheet thickness: approx. 2.5 mm -Cutting length: endless (unlimited) -Cutting method: 2 rotating circular knives -Knife diameter: approx. 120 – 150 mm -Table size: approx. 500 x 250 mm -Overhang / feed area: approx. 250 mm -Motor power: 0.75 – 1.1 kW Djdpfx Aeztctwel Soku -Drive: belt drive -Straight cuts -Strip cutting -Endless cutting of sheet metal -Steel sheet up to approx. 2.5 mm -Aluminum and non-ferrous metals, correspondingly thicker Dimensions: L x W x H 0.6 x 0.9 x 1.1 meters / Weight 180 kg Errors and omissions excepted

Condition: ready for operation (used), functionality: fully functional, machine/vehicle number: 13.707, working width: 6,200 mm, sheet thickness (max.): 6 mm, power: 11 kW (14.96 HP), overall weight: 17,500 kg, throat depth: 60 mm, TECHNICAL DETAILS Max. sheet thickness: 6 mm Max. working width: 6,200 mm Overhang: 60 mm Back gauge type: Electric Back gauge depth: 1,000 mm Angle adjustment: Motorized Sheet support system: Pneumatic MACHINE DETAILS Power: 11 kW Drive type: Hydraulic Dksdpfx Ajzuwzrsl Ssu Control: Conventional Control system: Elgo Dimensions & Weight Overall length: 6,400 mm Shipping weight: 17,500 kg EQUIPMENT CE certificate Documentation

Condition: ready for operation (used), Year of construction: 1979, Immediately available ex-works: Swivel bending machine, Lotze Type 161 / 2500 / 6 Year of manufacture 1979 Bending length 2550 mm Material thickness up to 6 mm Drive power 7.5 kW Weight 6 tons Dkedpoz Ixnwofx Al Sju Price: EUR 5,500.00 (plus VAT) ex-works.

Year of construction: 2017, condition: excellent (used), functionality: fully functional, machine/vehicle number: 004/2017, The line (multi-purpose automatic machine) is designed for the automatic straightening and cutting of uncoiled flat and metal strip and coil into sheets of various dimensions, with a simultaneous stacking system. The machine was manufactured in Poland in 2017. Main technical and operational parameters of the line: Dkodpfoz Eafxjx Al Ssu 1. Overall external dimensions of the entire line: total length – 1230 cm, maximum height – 180/260 cm, maximum width – 320 cm, 2. Length/width/height: receiving table – 400 cm, 130 cm, 87 cm; feeding table – 400 cm, 150 cm, 87 cm. 3. Power supply: electrical 3 x 400V/50Hz 4. Flat sheet parameters – thickness 0.5 mm – 2.0 mm / width – max 1500 mm, perforated sheet parameters – thickness up to 3 mm, width – max 1500 mm. 5. Uncoiling, straightening, and cutting speed – automatically controlled. 6. Max. Load – 5000 kg (5T) [spindle carriage]. Machine construction: 1. Rail carriage, 2. Coil unwinder – for strip and coil, 3. Straightener with adjustable straightening gap, 4. Guillotine shears – for transverse cutting of the strip into sheets, 5. Stacker (trap) for preliminary collection of sheet metal, 6. Wheel-and-spindle carriage for packaging sheet metal, 7. Control cabinet – integrated electrical and electronic systems for power supply, programming, and control. 8. Adjustable control panel with a visual touch screen. 9. Safety devices – guards, emergency stop switches, wire circuit with limit switch, distinctive colors. The construction of the machines that make up the line is based on a monolithic, compact frame and table structure made of steel profiles, angles, closed profiles, flat bars, bracing, and sheet metal cladding. The components are joined by longitudinal, butt, and lap welding, as well as by detachable bolted connections. The machine has been used very little (a few dozen operating hours) due to a change in production plans. It is in perfect condition. The stated price is the net price.

Condition: ready for operation (used), functionality: fully functional, Year of construction: 2017, machine/vehicle number: 6.088.177.254, controller model: Durma DT-7, working width: 3,100 mm, sheet thickness (max.): 13 mm, overall weight: 11,800 kg, TECHNICAL DETAILS Max. sheet thickness: 13 mm Max. working width: 3,100 mm Overhang: 50 mm Design: Swing-beam Angle adjustment: Manual Shear gap adjustment: Motorized Back gauge type: Electric Back gauge depth: 1,000 mm MACHINE DETAILS GENERAL Control system: CNC Controller: Durma DT-7 Drive type: Hydraulic Power: 30 kW Djdszuwvvspfx Al Sjku Dimensions & Weight Dimensions (L x W x H): 4,200 x 2,350 x 2,350 mm Weight: 11,800 kg Transport packages: 1 unit EQUIPMENT CE marking Finger guard: Fixed with fold-up guard Table type: Ball-bearing table

Condition: good (used), Swivel bending machine, a press brake from the renowned manufacturer Schröder. Capacity: 3mm steel, aluminum, etc., and more. Working width: approximately 2.04m. Weight: approximately 2.4 tons. Easy to operate. Manual and foot controls. Optionally, a segmented upper beam or a back gauge is available. The machine comes from private use. Loading with a forklift is no problem. On-site testing is, of course, possible. Dsdpfx Ajz Ad Rvjl Sjku You will receive an invoice according to §25a UStG – the VAT is included in the invoice amount. Subject to differential taxation. Optionally, a matching plate shear, 2m, 3mm, is available – a set price is also possible. Other equipment and tools for sheet metal processing are available.

Condition: ready for operation (used), Year of construction: 1985, control type: manual, working width: 4,080 mm, sheet thickness steel (max.): 10 mm, back gauge: 1,000 mm, power: 22 kW (29.91 HP), overall weight: 16,500 kg, total length: 5,300 mm, total width: 2,500 mm, total height: 2,300 mm, Cutting length 4080 mm, cutting capacity 10 mm, motor 22 KW, working high 800 mm, back gauge 1000 mm motorised, cutting line, footpedal, 4 frontarms, maschine can be lower down by 200 mm, dimension 5300x2500x2300 mm, ca. 16000 kgs Dodpfehl Im Njx Al Ssku

Condition: good (used), You are bidding on: a branded device – a press brake, from a very good and well-known manufacturer – Schechtl. New list price 2024 – see pictures (now more expensive again) €18,490 net, excluding the radius beam. Dedpfjzgt Nvex Al Ssku Features of the device: Press brake Schechtl HA Beam bends cleanly – testing possible Degree indicator Bending length slightly over 2m Sheet metal thickness 2 mm steel – sheet – aluminum, zinc, etc., up to approx. 3 mm Beam radius for aluminum, zinc is installed – a sharp beam is also included (see picture)! Optional: depth stop Sheet metal shear HT 200 or sheet metal shear Schröder electric 2m - 2.5mm would be optional. Important! Optionally, you can find and purchase many machines and machine accessories, such as various beams, depth stops – everything related to sheet metal and steel processing, such as press brakes, sheet metal shears, drilling machines, rounding machines, slitting and profiling machines – accessories (beading device, round rollers for gutter production, backstop, etc.), as well as other hand tools and spare parts from many top manufacturers in our shop. I am always available to answer your questions. You will receive an invoice in accordance with §25 a UStG – the value-added tax is included in the invoice amount. Subject to differential taxation. Free loading is possible – weight approx. 1450 kg. Inspection and testing are possible and welcome after a telephone appointment has been arranged. Payment in cash upon collection. Take advantage of our experience and expertise; we will be happy to advise you. Collection by the buyer himself (or by a forwarding agent commissioned by the buyer) should take place within 10 days after the end of the auction. Location: 97261 Güntersleben Article number: Press brake HA 200

Condition: ready for operation (used), Year of construction: 1989, functionality: fully functional, machine/vehicle number: 641/302, total width: 600 mm, total length: 800 mm, total height: 1,300 mm, overall weight: 120 kg, No minimum price – guaranteed sale to the highest bidder! Submitting a bid obligates you to collect the item within the specified timeframe between November 16, 2026, and November 26, 2026! MACHINE DETAILS Operating voltage: 380 V Frequency: 50 Hz Rated current: 30 A Connected load: 8.1 kW Dkjdpfx Alsz Il Ike Seu Dimensions & Weight Dimensions (L x W x H): 800 x 600 x 1,300 mm Weight: 120 kg External Reference: Steinbach & Holler - Lot 62

Condition: good (used), You are bidding on: a branded device – a press brake, from a very good and well-known manufacturer – Schechtl. Features of the device: Press brake Schechtl MA 200 / 6 The bending beam bends cleanly – testing is possible. Angle adjustment for up to 6 bending steps (if only 2-3 or, for example, 4 are needed, simply set it to the desired number). Ideal for series bending. The machine was used by a carpenter. Bending length slightly over 2m. Sheet thickness: 2 mm iron – sheet – aluminum, zinc, etc., up to approx. 3 mm. Standard bending beam – radius for aluminum, zinc would also be available as an option, as would an extension and special bending beam! Foot pedal for operation. Optional depth stop. Sheet metal shear HT 200, or MT (see picture) – or sheet metal shear Schröder electric 2m – 2.5mm would be optional, but not included in the price – the offer can be adjusted. Important! You can optionally find and purchase many machines and machine accessories, such as various bending beams, depth stops – everything related to sheet metal and steel processing, such as press brakes, sheet metal shears, drilling machines, circular machines, slitting and profiling machines – accessories (beading device, round rollers for gutter production, back gauge, etc.), as well as other hand tools and spare parts from many top manufacturers in our shop. I am always available to answer your questions. You will receive an invoice according to § 25 a UStG; the VAT is included in the invoice amount. Differential taxation. Free loading is possible – weight approx. 1700 kg. Inspection and testing are possible and desirable after arranging an appointment by telephone. Payment in cash upon collection. Take advantage of our experience and expertise; we will be happy to advise you. Dkjdpszzff Sjfx Al Sou Collection by the buyer himself (or by a forwarding agent commissioned by the buyer) should take place within 10 days after the end of the auction. Location: 97249 Eisingen, approx. 3 minutes from the A3 and A81 motorways. Article number: Press brake MA 200 / 6

Condition: used, Year of construction: 2011, total length: 3,800 mm, total width: 2,000 mm, total height: 1,900 mm, Colour: Grey Weight: 6.000 kg - Year: 2011 - Documentation available: Yes - CE marking present: Yes - CE certificate present: No - Serial number: 22106 - Drive system: Teach-in - Drive type: Hydraulic - Power [kW]: 11.0 - Max. sheet thickness [mm]: 6 - Max. working width [mm]: 3100 - Cutting speed [mm/min]: 22 - Backgauge depth [mm]: 1000 - Options: Digital readout - Transport dimensions: 3800mm x 2000mm x 1900mm (l x w x h) - Transport weight [kg]: 6000kg - Transport packages [pcs.]: 2 Financial information VAT: The price shown is exclusive of VAT Dkjdpfx Ajy Nk S Ajl Sou VAT/margin: VAT deductible for entrepreneurs Delivery and trade-in always possible for everything in the industrial sectors Lukas van Rossum

Condition: new, Year of construction: 2026, For sale is a new guillotine shear directly from the manufacturer Prod-Masz. Dkjdpfx Alecvqnyj Sou Visit our website to see our other products. Guillotine shears manually 1500 / 1.5mm the working length: 1500mm to sheet steel up to 1.2mm, Weight: 400 kg We are looking forward to your contact! The invoices are issued either with 0% of VAT as intra-Community delivery.

Condition: used, Year of construction: 1994, total length: 4,100 mm, total width: 1,900 mm, total height: 1,750 mm, Colour: Blue Weight: 6.500 kg Dkodpfx Aey Nk R Sel Sju - Year: 1994 - Documentation available: No - CE marking present: Yes - CE certificate present: No - Serial number: 10.769/94 - Drive system: Conventional - Drive type: Hydraulic - Power [kW]: 16.0 - Max. sheet thickness [mm]: 6 - Max. working width [mm]: 3150 - Throat depth [mm]: 160 - Backgauge depth [mm]: 1000 - Options: Digital readout - Transport dimensions: 4100mm x 1900mm x 1750mm (l x w x h) - Transport weight [kg]: 6500kg - Transport packages [pcs.]: 1 Financial information VAT: The price shown is exclusive of VAT VAT/margin: VAT deductible for entrepreneurs Delivery and trade-in always possible for everything in the industrial sectors Lukas van Rossum

Condition: excellent (used), Year of construction: 1997, machine/vehicle number: M0335, Cyril Bath type 20 T Hydraulic Swing Arm Profile Stretch Forming Machine year 1997 serial number M0335 capacity 20 t engine power 126 kW electric connection 400 V description With control Cyril Bath Monitor Type: Flexscan 685 12 CNC axes 4 auxiliary axes Stretching force 20–200 kn Bending angle 2 x 95 degrees Rotation stretching cylinder 2x –45/225 degrees Component length from 762 to max 3810 mm Hydraulics from Rexroth with 2 x hydraulic pumps: 45 kW each Dodpfxeqcu Aco Al Soku Various spares available

Condition: ready for operation (used), You are bidding on a press brake from the well-known German manufacturer, Biegemaster. Features of the machine: Bending length: slightly over 4m Sheet metal thickness (steel): 2mm Adjustable bending angle (see picture) Emergency stop Sheet metal support Control panel operation An advantage of this design is that sheets that have already been bent can also be bent again on the side. Free loading is possible. For approximately €2,000, I can arrange for a slitting shear to be included. You will receive an invoice in accordance with §25 a UStG. I can arrange transport with a shipping company if desired. Free loading as shown in the pictures. Inspection and testing are possible after arranging an appointment by phone. Payment in cash upon collection. If there is anything else I can do for you, please call me briefly. Thank you. Collection should take place within 8 days after the end of the auction. Location: 97249 Eisingen (3 minutes from the highway) Article number Dodpfx Alszcw Ucj Soku

Condition: new, Year of construction: 2026, Heavy duty manual guillotine shear for trade and industry. With the manual guillotine shear GLT you can make the perfect cut with every job. the extending table makes it easier to guide large-sized metal sheets on the table Support table with graduation robust and compact steel construction high quality, durable steel knife extremely stable and heavy construction made of cast iron ground and hardened guillotine shears Back gauge system with Scala CE mark Declaration of conformity stable and robust construction for steel plates up to 1.2mm Working length 2050mm open design suitable for endless cuts large cast work table Lower storage compartment for storing sheet metal pieces in the price Dimensions: Length: 2500mm Width: 750mm Height: 1150mm Weight: approx. 500 kg Passage: 8cm Dkodpfx Aecl D Hlsl Ssu Price: 4650 euros marking template free! Delivery date: every week Contact what's app We are looking forward to your contact! We issue the invoices with 0% (intra-community delivery)

Condition: used, Year of construction: 2023, functionality: fully functional, machine/vehicle number: 625RS10HWPp-D22092022, coil weight: 10,000 kg, feed rate X-axis: 35 m/min, number of straightening rollers: 5, sheet thickness aluminum (max.): 2 mm, sheet thickness steel (max.): 2 mm, sheet thickness copper (max.): 2 mm, inner diameter: 508 mm, sheet thickness (max.): 2 mm, outer diameter: 1,250 mm, mandrel diameter: 508 mm, coil width: 1,250 mm, coil outer diameter: 1,250 mm, number of blades: 8, type of input current: three-phase, working width: 1,250 mm, total width: 4,500 mm, total length: 5,700 mm, total height: 1,600 mm, load capacity: 10,000 kg, product width (max.): 1,250 mm, space requirement width: 4,500 mm, space requirement length: 5,700 mm, space requirement height: 1,600 mm, Krasser Centurio SCS-1250 slitting line with a Stolarczyk 10-ton motorized uncoiler For sale: a complete coil-fed sheet metal cutting and slitting line, manufactured by Krasser GmbH (Austria), installed new in January 2023 and used in-house ever since by a sheet metal processing company. Well-maintained, fully operational, and available for inspection while still running at our facility. Krasser Centurio SCS-1250 – slitting/cutting line Max. sheet/coil width: 1,250 mm — min. independent sheet width: 250 mm — min. slitting width: 75 mm between knives Material thickness range: steel (400 N/mm²) 0.4–1.5 mm, stainless steel (550 N/mm²) 0.4–1.0 mm, copper and aluminum 0.5–2 mm Max. cutting speed: 35 m/min Straightening unit: 5 rollers Longitudinal cutting: 6 pairs of slitting knives installed (5 standard + 1 additional pair), max. 8 Cross-cutting: electrically driven guillotine shear Roller-shear unit for partial cross-cuts included Automatic film-application (plastic protective film) unit included Automatic labeling unit included (label printer + applicator) Krasser Optimizer cutting-optimization software included Touchscreen HMI control, multilingual (including Spanish) CE-certified safety fencing Electrical connection: 3-phase 400–488V, 11 kW, 16A Pneumatic connection: 1/2", 6 bar, filtered and dried air, 50 l/min Approx. overall footprint (line + uncoiler): 5.7 m long x 4.5 m wide x 1.6 m high Lifetime production data (as of today): 176,941 m of material processed, 60,610 cross-cuts — machine has been in steady, reliable production use Stolarczyk uncoiling set (motorized, 10 tons) Manufacturer: Spółka Stolarczyk (Poland) — Type RS10HWPp-D, year 2022 Max. coil load: 10,000 kg (10 tons) Dkjdpfx Asz D Ivvol Ssu Hydraulic mandrel expansion — mandrel/coil inner diameter 508–610 mm Max. coil outer diameter: 1,250 mm — coil width: 250–1,250 mm Max. unwinding speed: 30 m/min Coil car included, with hydraulic vertical lift (306 mm) and electric horizontal travel Electrical connection: 400V, 6.5 kW Weight: 3,150 kg The line and uncoiler are sold together as a working unit. Removal/dismantling and logistics to be agreed with the buyer. For technical questions or to arrange a visit, please contact us by email — we're glad to answer any question and share further documentation, photos, or a video of the machine running.

Condition: new, Year of construction: 2026, ABKANTBANK-Technik KRUSE, Your competent partner for bending machines. Standard equipment includes piano inserts (segment-divided upper, lower, and bending jaws) for a wide range of bending options. With this model, it is easy to produce cassettes and special profiles with opposing bends. Swivel bending machine, universally applicable for sheet metal workshops, repair shops, and roofing companies. Segments can be individually moved and removed. Segment bending machine SGR 1400/1.5 Technical data: - max. working width: 1400 mm Other dimensions, 1000 mm and 2050 mm, available upon request. - Segments: 30, 40, 50, 60, 70, 100 mm - Bending angle max. 160 degrees - max. sheet thickness (steel) 1.5 mm - Weight: 285 kg Option to mount a guide rail for a slitting shear: 300 EUR Accessory: Slitting shear (up to 0.8 mm): 350 EUR Please note that all prices are subject to an additional 19% VAT. CE certificate Warranty: 12 months. Self-collection is possible. Dkjdpozuva Hsfx Al Seu Shipping within Germany: 180 EUR.

Condition: used, Year of construction: 1988, total length: 3,500 mm, total width: 2,000 mm, total height: 2,000 mm, Colour: Grey Weight: 4.600 kg - Year: 1988 - Documentation available: Yes - CE certificate present: No - Serial number: 14685 - Drive system: Conventional - Drive type: Hydraulic - Power [kW]: 7.5 - Max. sheet thickness [mm]: 6 - Max. working width [mm]: 3100 - Backgauge type: Electric - Backgauge depth [mm]: 750 Dkodpfxoyl Uvpo Al Seu - Sheet support system: None - Finger guard: Fixed - Angle adjustment: Manual - Blade gap adjustment: Manual - Table type: Standard table - Transport dimensions: 3500mm x 2000mm x 2000mm (l x w x h) - Transport weight [kg]: 4600kg - Transport packages [pcs.]: 1 Financial information VAT: The price shown is exclusive of VAT VAT/margin: VAT deductible for entrepreneurs Delivery and trade-in always possible for everything in the industrial sectors Lukas van Rossum

Condition: used, total length: 3,700 mm, total width: 1,600 mm, total height: 1,700 mm, Colour: Grey Weight: 4.500 kg - Documentation available: Yes - CE certificate present: No - Drive system: Conventional - Drive type: Hydraulic - Power [kW]: 7.5 - Max. sheet thickness [mm]: 6 - Max. working width [mm]: 3050 - Backgauge type: Electric - Backgauge depth [mm]: 750 - Sheet support system: None - Finger guard: Fixed - Angle adjustment: Motorized - Blade gap adjustment: Manual - Table type: Standard table - Transport dimensions: 3700mm x 1600mm x 1700mm (l x w x h) - Transport weight [kg]: 4500kg - Transport packages [pcs.]: 1 Financial information VAT: The price shown is exclusive of VAT VAT/margin: VAT deductible for entrepreneurs Dodoymbhzopfx Al Seku Delivery and trade-in always possible for everything in the industrial sectors Lukas van Rossum

Condition: excellent (used), Year of construction: 2015, operating hours: 1,600 h, input voltage: 400 V, input frequency: 50 Hz, We are offering this used Plank R-380 deburring or edge rolling machine, manufactured in 2015, for sale. Machine type: R-380 Dsdpfx Aloz I S D Ee Seku Machine no.: 404 Year of manufacture: 2015 Rated voltage: 400 V Frequency: 50 Hz If you have any questions or require further information, please feel free to send us a message or call us.

Condition: used, total length: 4,000 mm, total width: 2,000 mm, total height: 1,800 mm, Colour: Grey Weight: 5.600 kg - Documentation available: Yes - CE certificate present: No - Drive system: Teach-in - Control system brand: Delem - Control system type: DAC-150 Dkjdpfx Aleyf Dcrs Seu - Drive type: Hydraulic - Power [kW]: 11.0 - Max. sheet thickness [mm]: 6 - Max. working width [mm]: 3050 - Backgauge type: Electric - Backgauge depth [mm]: 1000 - Sheet support system: None - Finger guard: Fixed - Blade gap adjustment: Manual - Table type: Standard table - Options: Digital readout - Transport dimensions: 4000mm x 2000mm x 1800mm (l x w x h) - Transport weight [kg]: 5600kg - Transport packages [pcs.]: 1 Financial information VAT: The price shown is exclusive of VAT VAT/margin: VAT deductible for entrepreneurs Delivery and trade-in always possible for everything in the industrial sectors Lukas van Rossum