subcategories automation equipment

cat.-No. 2nd category level results
2304 controllers 47
2305 other automation equipment 4,269
2301 robots 319
2302 sensors 60
2303 switches 13
2300 all automation equipment order by entry date descending 4,776

latest results automation equipment

2305 other automation equipment
Entry date: 12.05.2026 item-No.: 169490818
approved
dealer

used

Location: Land-de
Price: 800 € add to watchlist

used Schunk GWK 125 (302514) Gripper change system. Schunk Gripper Changing System GWK 125 (302514) Recommended weight: 170 kg Interlock detection: no Repeatability: ±0.04 mm Weight: 2.3 kg Max. locking distance: 2 mm Number of pneumatic feedthroughs: 8 Pneumatic feed-through with air connection thread: G1/8" Number of pneumatic feedthroughs: 2 Pneumatic feed-through with air connection thread: G1/4" Number of electrical feedthroughs: 36 Max. permissible XY offset: ±1.5 mm Max. permissible angle offset: ±1° Min. ambient temperature: 5 °C max. ambient temperature: 60 °C Min. operating pressure: 4.5 bar Max. operating pressure: 6 bar Max. torque Mx: 400 Nm Max. torque My : 400 [Nm] Moment Mz max. : 600 [Nm] Force Fz max. : 6000 [N] Force Fd max. : 9000 [N]

2305 other automation equipment
Entry date: 12.05.2026 item-No.: 169490815
approved
dealer

used

Location: Land-de
Price: 1.140 € add to watchlist

used Schunk PGF 100 AS (340381) Universal gripper. Schunk Universal Gripper PGF 100 AS (340381) Stroke per jaw 23.5 mm Clamping force 1150 N Clamping force (at finger length 0 mm) 1144 N Min. spring force 270 N Net weight : 2.85 kg Recommended workpiece weight 4.4 kg Cylinder volume per double stroke 154 cm³ Min. operating pressure 4 bar Max. operating pressure 6.5 bar Nominal operating pressure 6 bar Closing time 0.16 s Opening time 0.25 s Closing/opening time with spring 0.7 s Max. permissible finger length 100 mm Max. permissible mass per finger 1.4 kg Protection class IP 40 Min. ambient temperature 5 °C Max. ambient temperature 90 °C Repeatability : 0.03 mm Length X 148.5& ...

2305 other automation equipment
Entry date: 12.05.2026 item-No.: 169490812
approved
dealer

used

Location: Land-de
Price: 1.290 € add to watchlist

used Schunk PGNplus 380-1 AS (371407) Universal gripper. Schunk Universal Gripper PGNplus 380-1 AS (371407) Stroke per jaw [mm]: 45.0 Clamping force [N]: 12350.0 Clamping force (at finger length 0 mm) [N]: 12990.0 Min. spring force [N]: 3300.0 Net mass [kg]: 36.5 Recommended workpiece weight [kg]: 47.0 Cylinder volume per double stroke [cm³]: 2705.0 Min. Operating Pressure [bar]: 4.0 Max. Operating Pressure[bar]: 6.5 Nominal operating pressure [bar]: 6.0 Min. sealing air pressure [bar]: 0.5 Max. sealing air pressure [bar]: 1.0 Closing time [s]: 0.5 Opening hours [s]: 0.8 Closing/opening time with spring [s]: 0.8 Max. permissible finger length [mm]: 350.0 Max. permissible mass per finger [kg]: 17.0 Protection class IP: 40 Min. ambient temperature [°C]: 5.0 Max. Ambient Temperature [°C]: 90.0 Repeatability [mm]: 0.05 Length X [mm]: 410.0 Width Y [mm]: 170.0 Hei ...

2301 robots
Entry date: 12.05.2026 item-No.: 169490809
approved
dealer
New in: 2020

used

Location: Land-de
Price: 16.200 € add to watchlist

used Cobot UR5 Industrial robots. Robot Cobot Universal Robots UR5 Year of Make: 2020 Number of axes: 6 Max. load capacity: 5 kg Max. working range: approx. 850 mm Scope of delivery: robot, controller, cable, teach panel In addition, spare parts are always available from stock. The robot is fully functional and can be visited. 2 weeks commissioning warranty. No further warranty.

2301 robots
Entry date: 12.05.2026 item-No.: 169490806
approved
dealer
New in: 2018

used

Location: Land-de
Price: 10.600 € add to watchlist

used Cobot Aubo-i5 Industrial robots. Collaborative robot cobot Aubo-i5 built in 06/2018 Was only used for test purposes Scope of delivery: 1) Robot Cobot Aubo i-5 Manipulator SerialNr. ABCE18061010IV4 Weight: 24 kg 2) Aubo i5 control box, model CB, Serial No. ABCE18061010IV4 Weight: 31 kg In addition, spare parts are always available from stock. The robot is fully functional and can be visited. 2 weeks commissioning warranty. No further warranty.

2301 robots
Entry date: 12.05.2026 item-No.: 169490803
approved
dealer
New in: 2017

used

Location: Land-de
Price: 14.900 € add to watchlist

used Cobot Universal Robots UR5 komplett Industrial robots. Robot Cobot Universal Robots UR5 complete only approx. 4487 operating hours Year of manufacture: 1/2017 Number of axes: 6 Max. load capacity: 5 kg Max. working range: approx. 850 mm Scope of delivery: robot, controller, cable, teach panel In addition, spare parts are always available from stock. The robot is fully functional and can be visited. 2 weeks commissioning warranty. No further warranty.

2301 robots
Entry date: 12.05.2026 item-No.: 169490802
approved
dealer

used

Location: Land-de
Price: 17.800 € add to watchlist

used ABB Robotics IRB 2600 20/1.65 IRC5 M2004 Industrial robots. ABB Robotics IRB 2600 20/1.65 IRC5 M2004 Robot , Multimove 12 Axis, 2 Robots Number of axes: 12 Max. load capacity: 20 kg Max. working range: 1650 mm Year of manufacture: 9/2014 Scope of delivery: 2x robot mechanics, Multimove 12-axis control cabinet, teach panel, connecting cables In addition, spare parts are always available from stock. The robot is fully functional and can be visited. 2 weeks commissioning warranty. No further warranty.

2301 robots
Entry date: 12.05.2026 item-No.: 169490801
approved
dealer
New in: 2021

used

Location: Land-de
Price: 11.700 € add to watchlist

used Cobot JAKA JAKA ZU 7, CAB 12 Industrial robots. Robot Cobot JAKA ZU 7 , CAB 12 , YOC 2021 complete 2 pieces available 1x 950mm 1x 819mm Price is for 1 piece Year of Make: 2021 Number of axes: 6 Max. load capacity: 7 kg Max. working range: approx. 819/954 mm Scope of delivery: robot, controller, cable, software In addition, spare parts are always available from stock. The robot is fully functional and can be visited. 2 weeks commissioning warranty. No further warranty.

2301 robots
Entry date: 12.05.2026 item-No.: 169490799
approved
dealer
New in: 2014

used

Location: Land-de
Price: 7.900 € add to watchlist

used ABB Robotics IRB 2600 20/1.65 IRC5 M2004 Industrial robots. Robot ABB Robotics IRB 2600 20/1.65 IRC5 M2004 , mechanics only Number of axes: 6 Max. load capacity: 20 kg Max. working range: 1650 mm Year of manufacture: 9/2014 Scope of delivery: robot mechanics In addition, spare parts are always available from stock. The robot is fully functional and can be visited. 2 weeks commissioning warranty. No further warranty.

2301 robots
Entry date: 12.05.2026 item-No.: 169490798
approved
dealer
New in: 2008

used

Location: Land-de
Price: 12.000 € add to watchlist

used ABB Robotics IRB 1600 8/1.45 IRC5 M2004 Industrial robots. Robot ABB Robotics IRB 1600 8/1.45 IRC5 M2004 , complete Control: IRC5 M2004 Number of axes: 6 Max. load capacity: 8 kg Max. working range: 1450 mm Year of Make: 2008 Scope of delivery: robot, controller, cable, teaching panel, circuit diagrams In addition, spare parts are always available from stock. The robot is fully functional and can be visited. 2 weeks commissioning warranty. No further warranty.

2301 robots
Entry date: 12.05.2026 item-No.: 169490793
approved
dealer
New in: 2006

used

Location: Land-de
Price: 6.200 € add to watchlist

used KUKA KRC2r + KCP2 + KR5 sixx R850 Industrial robots. Kuka robot KRC2sr + KCP2 + KR5 sixx R850 Number of axes: 6 Max. load capacity: 5 kg Max. intervention: 850 mm Year of Make: 2006 Scope of delivery: robot, controller, cable, teaching panel, operating instructions, circuit diagrams. In addition, spare parts are always available from stock. The robot is fully functional and can be visited. 2 weeks commissioning warranty. No further warranty.

2301 robots
Entry date: 12.05.2026 item-No.: 169490792
approved
dealer
New in: 2021

used

Location: Land-de
Price: 6.500 € add to watchlist

used Elite Robots Cobot EC63 Industrial robots. Robot Elite ROBOTS Cobot EC63 complete approx. 7392 operating hours Year of construction: 9/2021 Number of axes: 6 Max. load capacity: 3kg Max. working range: approx. 624mm Scope of delivery: robot, controller, cable, teach panel In addition, spare parts are always available from stock. The robot is fully functional and can be visited. 2 weeks commissioning warranty. No further warranty.

2301 robots
Entry date: 11.05.2026 item-No.: 169482733
approved
dealer
New in: 2011

used

Location: Land-de
Price: 8.600 € add to watchlist

used Fanuc LR Mate 200iC Controller R-30i Industrial robots. Roboter Fanuc Robot LR Mate 200iC Robot Controller R-30iA Mate Year of Make: 2011 Scope of delivery: Robot LR Mate 200iC Type A05B-1139-B204 I Pendant A05B-2518-C202#EGN Fanuc System R-30iA Mate Type A05B-2553-B061 Cables Two weeks commissioning guarantee. No further warranty.  In addition, spare parts are always available from stock. The robot is fully functional and can be visited.

2301 robots
Entry date: 05.05.2026 item-No.: 169449012
approved
dealer
New in: 2017

used

Location: Land-de
Price: 10.500 € add to watchlist

used KUKA KR10 R900 sixx Industrial robots. KUKA Robot KR 10 R900 sixx robot (85.7 operating hours) Year of manufacture: 02/2017 Load: 10 kg Reach: 901.5 mm Smart Pad: KRC4 00-168-334 Control: KRC4 compact Cable: yes Colour: orange Operating hours: 85.7 h Condition: perfect condition, only in operation for test purposes Note: Robot was in a development center for testing purposes

2301 robots
Entry date: 05.05.2026 item-No.: 169449009
approved
dealer
New in: 2015

used

Location: Land-de
Price: 25.800 € add to watchlist

used KUKA KR600 R2830 Industrial robots. KUKA Robot KR 600 R2830 robot (50.3 operating hours) Year of manufacture: 09/2015 Load: 600 kg Reach: 2826 mm Smart Pad: KRC4 00-168-334 Control: KRC4 Cable: yes Colour: orange Operating hours: 50.3 h Condition: perfect condition, only in operation for test purposes Note: Robot was in a development center for testing purposes

2301 robots
Entry date: 05.05.2026 item-No.: 169449008
approved
dealer
New in: 2016

used

Location: Land-de
Price: 11.800 € add to watchlist

used KUKA KR10 R1100 Industrial robots. KUKA Robot KR 10 R1100 sixx robot (367 operating hours) Year of manufacture: 10/2016 Load: 10 kg Reach: 1101 mm Smart Pad: KRC4 00-168-334 Control: KRC4 compact Cable: yes Colour: white Operating hours: 367 h Condition: good condition, only in operation for test purposes Note: Touchscreen on the smartpad is defective, robot was in a development center for test purposes

2301 robots
Entry date: 05.05.2026 item-No.: 169449007
approved
dealer
New in: 2014

used

Location: Land-de
Price: 12.200 € add to watchlist

used KUKA KR 210 R3300 K-Foundry Industrial robots. Robot KUKA Robot KR 210 R3300 K – Foundry ultra (45 operating hours) Year of manufacture: 06/2014 Load: 210 kg Reach: 3300 mm Smart Pad: no Control: KRC4 Cable: no Colour: orange Operating hours: 45 h Condition: perfect condition, only in operation for test purposes Note: Foundry Edition, designed for harsh environments. Robot was in a development center for test purposes

2301 robots
Entry date: 05.05.2026 item-No.: 169449006

used

Location: Land-de
Price: VB 12.000 € add to watchlist

used Fanuc R-2000iC/165F Palletizing Robot/6-Axis Robot/Industrial Robot. We are selling the stock of the soap factory Riesa here In the last picture you will find an overview picture of the production hall with the machine inventory. Here we offer you: 1 palletizing robot 6-axis robot, for payloads up to 165 g, set to Euro pallet dimensions, robot reach 2655 mm, The robot is energized due to programming, installation dimensions 771 x 610 mm, average power 2.5 kW, electrical voltage 380 - 575 V, mechanical protection IP54, wrist and arm protection IP67 The plant was shut down in 2024. Roller conveyor and feed conveyor belt can be purchased for an extra charge

2302 sensors
Entry date: 02.05.2026 item-No.: 169433536
New in: 2019

used

Location: Land-de
add to watchlist

used Fiesseler Light barriers. Light barriers 50cm like new

2304 controllers
Entry date: 27.04.2026 item-No.: 169403292
approved
dealer

used

Location: Land-at
Price: VB 500 € add to watchlist

used BOSCH Indramat CNC Control Servo Motor. Tyristor amplifier Indramat from milling machine for controlling DC motors, incl. connection diagrams, transformers, transform 1 pc. 3 TRM 2 – G11 , for 3 axes, programming module TSS11/ 109, 144, 109 1 pc. 1 TRM 3 W23-W0 for 1 axle, TSS8 535-1 1 pcs. TRK 6 – 4U 380 , Tyristor Control Amplifier for Milling Motor, Programming Module TSS10-527 Price per piece: Euro 400,- 1 pc DC servo motor Indrumat, type: 2 G 1115 1 R-B3-3303 H2, speedometer TDC 2.6 H1 Price : Euro 500,- 2 pcs permanent magnet DC servo motor, Indrumat, type: MDC 10.40C / MMA-0/ S06

2304 controllers
Entry date: 27.04.2026 item-No.: 169403287
approved
dealer

used

Location: Land-at
Price: VB 300 € add to watchlist

used BOSCH Indramat CNC Control Servo Motor. Tyristor amplifier Indramat from milling machine for controlling DC motors, incl. connection diagrams, transformers, transform 1 pc. 3 TRM 2 – G11 , for 3 axes, programming module TSS11/ 109, 144, 109 1 pc. 1 TRM 3 W23-W0 for 1 axle, TSS8 535-1 1 pcs. TRK 6 – 4U 380 , Tyristor Control Amplifier for Milling Motor, Programming Module TSS10-527 Price per piece: Euro 300,- 1 pc DC servo motor Indrumat, type: 2 G 1115 1 R-B3-3303 H2, speedometer TDC 2.6 H1 Price : Euro 400,-

2301 robots
Entry date: 23.04.2026 item-No.: 169381776
ankerimg

used

Location: Land-my
Price: 160.000 USD add to watchlist

used TGI F25 R&D ROBOTIC SIMULATOR. Selling system as a whole including: 1. Robotic arm FANUC M-710iC50. 2. Controller R-30iA with teach pendant. 3. All tanks and ovens. 4. All motors. 5. Panel Currency: MYR PIC:  - Dr. Wong Sze Ting (013 939 6151/ wongsttopglove.com.my) - Ms. Fatimah (013 628 7197/ fatimah_asmadtopglove.com.my) - Ms, Farha ( 01111936236/ nurfarha_atopglove.com.my

2301 robots
Entry date: 22.04.2026 item-No.: 169375756
approved
dealer
New in: 2004

used

Location: Land-pl
Price: 2.900 € add to watchlist

used KUKA KR210 Industrieroboter. Quantity: 2 pieces Brand: KUKA Model: KR210 Year of construction: 2004 Length: 700 cm Width: 450 cm Height: 320 cm

2301 robots
Entry date: 22.04.2026 item-No.: 169375755
approved
dealer
New in: 2002

used

Location: Land-pl
Price: 2.900 € add to watchlist

used KUKA KR210 Industrieroboter. Industrial robot, with cell Brand: KUKA Model: KR210 Year of construction: 2002 Machine Dimensions: Length: 700 cm Width: 550 cm Height: 320 cm

2301 robots
Entry date: 22.04.2026 item-No.: 169375751
approved
dealer

used

Location: Land-pl
Price: 2.900 € add to watchlist

used KUKA KR210 Industrieroboter. Industrial robot, with module Brand: KUKA Model: KR210 Machine Dimensions: Length: 170 cm Width: 100 cm Height: 220 cm

2301 robots
Entry date: 22.04.2026 item-No.: 169375750
approved
dealer
New in: 2001

used

Location: Land-pl
Price: 4.900 € add to watchlist

used KUKA KR30L 15/2 Industrieroboter. Year of manufacture: 2001 Control: (V)KRC2 Load capacity: 15kg Reach: 3085 mm

2301 robots
Entry date: 22.04.2026 item-No.: 169375748
approved
dealer
New in: 2012

used

Location: Land-pl
Price: 9.400 € add to watchlist

used KUKA KR 6 R900 SIXX Industrieroboter. Year of construction: 2012 Load capacity: 6 kg Reach: 901 mm

2301 robots
Entry date: 22.04.2026 item-No.: 169375746
approved
dealer
New in: 2021

used

Location: Land-pl
Price: 9.500 € add to watchlist

used KUKA 3 D1200 HM/SEL Industrieroboter. Hygienic robot, suitable for food and medical industry. Pick and Place Robot Model: KUKA 3 D1200 HM/SEL Number of available: 24 robots Year: 2021 Load capacity: 3 kg Reach: 1200 mm Control: KR C5 KSP

2301 robots
Entry date: 22.04.2026 item-No.: 169375735
approved
dealer
New in: 2018

used

Location: Land-pl
Price: 11.400 € add to watchlist

used KUKA KR 6 R900 sixx Industrieroboter. Year of manufacture: 2018 Weight: 52 kg Load capacity: 6 kg Reach: 901 mm Positioning: ±0.03mm Number of axles: 6 Control: KUKA KRC4

2301 robots
Entry date: 22.04.2026 item-No.: 169375730
approved
dealer
New in: 2017

used

Location: Land-pl
Price: 11.600 € add to watchlist

used KUKA KR 270 R2700 Ultra Industrieroboter. Model: KR 270 R2700 Ultra Version: C4 FLR (Floor) Year of manufacture: 2017 Load capacity: 270 kg Reach: 2696 mm Weight: 1129 kg Controller: KUKA KR C4 Serial Number: 663438

2301 robots
Entry date: 22.04.2026 item-No.: 169375727
approved
dealer
New in: 2015

used

Location: Land-pl
Price: 11.900 € add to watchlist

used KUKA KR 16-2 KS Industrieroboter. Country of manufacture: Germany Year of manufacture: 2015 Reach: 1801 mm Repeatability: +/- 0.5mm Number of axles: 6 Load capacity: 16 kg Control: KPC4 Weight: 245 kg

2301 robots
Entry date: 22.04.2026 item-No.: 169375721
approved
dealer
New in: 2015

used

Location: Land-pl
Price: 13.000 € add to watchlist

used KUKA KR 210 R2700 prime Industrieroboter. Model: KR 210 R2700 prime Serial Number: 642212 Year of manufacture: 2015 Payload: 210 kg Reach: 2696 mm Weight: 1111 kg

2301 robots
Entry date: 22.04.2026 item-No.: 169375716
approved
dealer
New in: 2017

used

Location: Land-pl
Price: 14.000 € add to watchlist

used KUKA KR360 R2830 Industrieroboter. Type: KR 360 R2830 Version: KR360R2830 C4 FLR / FLOOR Controller: KR C4 Load capacity: 360 kg Reach: 2826 mm Robot weight: 2385 kg Year of manufacture: 2017 The series No. (robot): 402267 Year of manufacture of the controller: 2017 The series No. (KR C4): 331300

2301 robots
Entry date: 22.04.2026 item-No.: 169375714
approved
dealer
New in: 2012

used

Location: Land-pl
Price: 14.000 € add to watchlist

used KUKA KR 240 R 2900 C ultra Industrieroboter. Year of manufacture: 2012 Control: KUKA KRC4 Lifting capacity: 240kg Reach: 2896mm

2301 robots
Entry date: 22.04.2026 item-No.: 169375711
approved
dealer
New in: 2011

used

Location: Land-pl
Price: 14.900 € add to watchlist

used KUKA KR 180 Industrieroboter. KUKA grinding cell with KR 180 robot Set Year of manufacture: 2011 Reach: 2498 mm Controls: Kuka KRC4 Load capacity: 180 kg We have 4 goals Remote control

2301 robots
Entry date: 22.04.2026 item-No.: 169375706
approved
dealer
New in: 2017

used

Location: Land-pl
Price: 16.900 € add to watchlist

used KUKA KR60 L30-3 Industrieroboter. KUKA KR60 L30-3 industrial robot Year of manufacture: 2017 Load capacity: 30 kg Reach: 2429 mm Control: KUKA KRC4 2 pcs available.

2305 other automation equipment
Entry date: 22.04.2026 item-No.: 169375673

used

Location: Land-th
Price: 3.350 USD add to watchlist

used 800 TS Protein machine type microplate reader bio-tek. PROTEIN MACHINE TYPE MICROPLATE READER BIO-TEK 800 TS Absorbance Reader with Gen5RC 1 Unit Detection modes: Absorbance Microplate types:6- to 384-well plates Temperature control: To 50 °C (I” configuration) Read speed:11 secs /96 wells (sweep mode) Brand: BioTek With Computer UPS 1.0KVA CONTACT INFORMATION (Ms) Supawadee Kumpone - Toy Manager, Procurement Mobile#: +6693-7478585 Email: supawadeegreatglove.com (Ms) Wilawan Sakulsongboonsiri Mobile#: +6689-1969222 Email: wilawan_sakultopglove.com

2305 other automation equipment
Entry date: 22.04.2026 item-No.: 169375670

used

Location: Land-th
Price: 2.400  US add to watchlist

used VELOCITY 18R Refrigerated centrifuge dybamica. Refrigerated Centrifuge " Dynamica " Model Velocity 18R - Maximum Speed 18,000 rpm : RCF 27070xg - LCD Display - Micro processor controller - Temperature range -20 to 40 C - Auto rotor recognition - Automatic lock rotor - 1 x FA15A Angle rotor 24 x 1.5/2 ml Speed 15,000 rpm , 21500xg - 1 x FA15C Angle rotor 6 x 50 ml - 6 x FA15.15C Adapter 6 x 15 ml Speed 15,000 rpm , 23,300xg CONTACT INFORMATION (Ms) Supawadee Kumpone - Toy Manager, Procurement Mobile#: +6693-7478585 Email: supawadeegreatglove.com (Ms) Wilawan Sakulsongboonsiri Mobile#: +6689-1969222 Email: wilawan_sakultopglove.com

2305 other automation equipment
Entry date: 22.04.2026 item-No.: 169375658

used

Location: Land-th
Price: 4.700 USD add to watchlist

used RX-5000 ALFA Automatic digital refractometer. AUTOMATIC DIGITAL REFRACTOMETER MDEL : RX-5000 ALFA BRAND : ATAGO TYPE : TOUCH SCREEN SCALE : Refractive index RANGE : Refractive index (nD) 1.32420 to 1.58000 BRIX : 0.000 to 100.00% SOLUTION : Refractive index (nD): 0.00001 Brix 0.01% temp 0.01C ACCURACY : Refractive index (nD): 0.00004 Brix 0.03% TEMP CONTROL RANGE : 5.00 to 75.00 C DIMENSION & WEIGHT : 37 x 24 x 14 6.6 kg POWER SUPPLY : AC100V to 240 V, 50/60Hz CONTACT INFORMATION (Ms) Supawadee Kumpone - Toy Manager, Procurement Mobile#: +6693-7478585 Email: supawadeegreatglove.com (Ms) Wilawan Sakulsongboonsiri Mobile#: +6689-1969222 Email: wilawan_sakultopglove

2301 robots
Entry date: 22.04.2026 item-No.: 169375646
approved
dealer
New in: 2015

used

Location: Land-pl
Price: 37.900 € add to watchlist

used KUKA KR 210 R2700 prime Industrieroboter. Kuka KR 210 R2700 prime grinding and cutting robot with rotary table. 2-axis Year of manufacture: 2015 Reach: 2700mm Control: KRC4 Rotary Table Load capacity: 210 kg Weight: 1111 kg Number of axles: 6 Axle Range: 1 axis ±185° 2 axis -140° / -5° 3 Axis -120°/155° 4 axis ±350° 5 axis ±122.5° 6 axis ±350°

RESALE since 1996 back