SO-100 vs SO-101: what changed?
The SO-101 is the newer arm: improved wiring, easier assembly with no gear removal, and updated leader-arm motors. The SO-100 docs are marked deprecated. Two-arm parts lists cost about the same: $229.88 for the SO-101 against $232 for the SO-100. Buy the SO-101.
Side by side
| SO-100 | SO-101 | |
|---|---|---|
| Status | Docs marked deprecated | Current version |
| Wiring and assembly | Older design | Improved wiring, no gear removal |
| Motors | 12 identical STS3215 at $15 each (two arms) | STS3215 in three gear ratios (7 x 1/345, 2 x 1/191, 3 x 1/147) at $13.89 each |
| Parts list, two arms (US) | $232 | $229.88 |
| 3D printing | One print tray per arm for Ender, Prusa/UP and Bambu A1 mini | 14 distinct parts per arm, PLA+, 0.2 mm layers, 15% infill |
| Assembly time | First arm a bit over 1 hour | Not stated in the docs |
All rows: TheRobotStudio/SO-ARM100 README and BOM, checked 7 Nov 2026. Gripper differences are not listed because we found no sourced comparison.
Which one to buy
New kits at the sellers we check are SO-101. Today's lowest in-stock SO-101 price: $249.90 at Seeed. See the SO-101 page.
People also ask
Are SO-100 parts compatible with the SO-101?
We found no sourced compatibility statement, so we do not claim one. Check the repository before mixing parts.
Does the SO-101 work with LeRobot?
Yes. Hugging Face documents the SO-101 in LeRobot. LeRobot SO-101 docs
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