WidowX 250 S
Trossen Robotics' Interbotix X-Series 6-DoF Dynamixel arm, now discontinued. It is the robot used for BridgeData V2, and the "WidowX" in OpenVLA, X-VLA and EO-1 real-robot results refers to this setup. It is not the Trossen WidowX AI (trossen-widowx). LeRobot shipped a native `widowx` teleoperator for this arm (the ALOHA leader role) until 0.3.3 and has never had a follower robot type for it. Policies are usually deployed through the BridgeData WidowX controller stack (rail-berkeley/bridge_data_robot) or Trossen's ROS packages.
LeRobot removedverified 2026-10-24aka WidowX 250, WidowX 250 S, WidowX-250 6DOF, wx250s, Interbotix WidowX 250, Bridge WidowX
Policies on WidowX 250 S 8 with evidence · 13 unknown
| Policy | State | Tier | Verified | Detail |
|---|---|---|---|---|
| ACT Imitation | partial | T1 · upstream documented | 2026-10-24 1d ago | The BridgeData V2 evaluation used goal-image-conditioned ACT. bridge_data_v2 does not include the ACT implementation or a checkpoint. |
| Diffusion Policy Imitation | partial | T3 · community reported | 2026-10-24 1d ago | Training evidenced by public checkpoint(s); on-robot inference not documented by a primary source. |
| EO-1 VLA | works | T1 · upstream documented | 2026-10-24 1d ago | |
| GR00T N1.7 VLA | partial | T1 · upstream documented | 2026-10-25 today | Simulation only: SimplerEnv WidowX + Bridge (N1.7 post-trained on BridgeData V2); no real-robot training or inference documented. |
| OpenVLA-OFT VLA | works with caveats | T1 · upstream documented | 2026-10-24 1d ago | The WidowX result is an appendix experiment: OpenVLA-OFT (without FiLM) trained on all of BridgeData V2 and evaluated on a subset of OpenVLA's Bridge tasks (69.2% vs. 65.8% for OpenVLA). |
| OpenVLA VLA | works | T1 · upstream documented | 2026-10-24 1d ago | |
| SmolVLA VLA | partial | T3 · community reported | 2026-10-25 today | Training evidenced by public checkpoint(s); on-robot inference not documented by a primary source. |
| X-VLA VLA | works with caveats | T1 · upstream documented | 2026-10-24 1d ago | The paper says only 'WidowX' following the BridgeData V2 benchmark. It identifies the arm through BridgeData V2 (a WidowX 250), not by model name. |
Not yet verified: Evo-1, Fast-WAM, HIL-SERL, LingBot-VA, MolmoAct2, Multitask DiT, π0-FAST, π0, π0.5, TD-MPC, VLA-JEPA, VQ-BeT, WALL-OSS. Have evidence?
Specifications
- Degrees of freedom
- 6src
- Payload
- ?–250 gsrc
- Repeatability
- ?–1 mmsrc
- Homepage
- www.trossenrobotics.com/widowx-250
Not the Trossen WidowX AI (trossen-widowx). Evidence for one does not transfer to the other. Trossen spec: 6 DoF, 650 mm reach, 1 mm repeatability, 5-8 mm accuracy, 250 g working payload. Trossen's product page marks the WidowX 250 S as discontinued. Results on the Bridge "WidowX" in SimplerEnv are simulation, not real-robot, evidence.
Framework support
| Framework | Support | Since | Type string | Docs |
|---|---|---|---|---|
| LeRobot | removed (until 0.3.3)src | — | — | — |
| ROS 2 | upstream-reposrc | — | — | docs |
| LeRobot: Only a teleoperator (`--teleop.type=widowx`, leader arm) was ever native. There was no follower robot type, so LeRobot could not run a policy on it. Deprecated in 0.4.0. | ||||
| ROS 2: Trossen's Interbotix X-Series ROS 2 packages (control, MoveIt 2, simulation). | ||||
Sources
- T1 · upstream documentedvendor-docsverified 2026-10-24 (1d ago)
Trossen spec for the WidowX-250 6DOF: 6 DoF, 650 mm reach, 1 mm repeatability, 250 g working payload.
“WidowX-250 6DOF Degrees of Freedom 6 Reach 650mm Total Span 1300mm Repeatability 1mm Accuracy 5 - 8mm Working Payload 250g*”
https://docs.trossenrobotics.com/interbotix_xsarms_docs/specifications/wx250s.html - T1 · upstream documentedvendor-docsverified 2026-10-24 (1d ago)
Trossen's WidowX 250 S product page shows a discontinued banner.
“THIS PRODUCT HAS BEEN DISCONTINUED”
https://www.trossenrobotics.com/widowx-250 - T1 · upstream documentedpapersource 2024-01-17verified 2026-10-24 (1d ago)
BridgeData V2 was collected on a WidowX 250 with a fixed RGBD over-the-shoulder camera, two randomized RGB cameras and a wrist camera, at 5 Hz control.
“showing the WidowX 250 robot arm and various cameras.”
https://arxiv.org/abs/2308.12952v3 - T1 · upstream documentedsource-codeverified 2026-10-24 (1d ago)lerobot 0.3.3
LeRobot v0.3.3 ships a `widowx` Teleoperator (Dynamixel XM430/XL430 bus) that links to the WidowX 250 product page.
“[WidowX](https://www.trossenrobotics.com/widowx-250) developed by Trossen Robotics”
https://github.com/huggingface/lerobot/blob/v0.3.3/src/lerobot/teleoperators/widowx/widowx.py - T1 · upstream documentedrelease-notessource 2025-10-23verified 2026-10-24 (1d ago)lerobot 0.4.0
LeRobot 0.4.0 deprecated its native stretch, viperx and widowx devices.
“chore(robots): deprecate strech, vipex and widowx robots by @imstevenpmwork in https://github.com/huggingface/lerobot/pull/2205”
https://github.com/huggingface/lerobot/releases/tag/v0.4.0 - T1 · upstream documentedvendor-docsverified 2026-10-24 (1d ago)
Trossen maintains ROS 2 packages for its X-Series arms, WidowX 250 6DOF included.
“Below is a list of all ROS 2 packages meant to be used with the X-Series robotic arms sold by Trossen Robotics.”
https://docs.trossenrobotics.com/interbotix_xsarms_docs/ros2_packages.html