K-Scale Labs (defunct) & community Z-Bot (Zeroth Bot) (1)

K-Scale Labs (defunct) & community Z-Bot (Zeroth Bot) (2)

K-Scale Labs (defunct) & community Z-Bot (Zeroth Bot) (3)

Not sold · DIY BOM from ~$350was $999; K-Scale shut down Nov 2025 and open-sourced everything

Discontinued · unavailableRL walkingCompany defunctOpen-sourced IPksim / MuJoCo

UnavailableShipping: Not available. Nobody sells it. DIY only, with Feetech servos from AliExpress (~2 weeks) plus printing. GitHub ↗

zeroth-bot ↗kos-zbot ↗Shutdown news ↗

Overview

Treat this as an archive, not a product. The repos remain and a few hobbyists still build them, but there is no vendor, no official docs, and the software is orphaned. The Duck and Microduck offer the same Feetech-class, MuJoCo-trained experience with a living community.

Specifications

Category	Bipeds · Open-source RL bipeds
Released	2024
Availability	Discontinued · unavailable
Programmability	Open source (hardware + software)
Best for	Ages 16+ (estimated)
Vision sensors	Camera
Actuators	Smart servos (Dynamixel, Feetech…)
Audio	Speaker, Microphone
Compute type	Raspberry Pi, Other ARM chip
Balance type	RL walking
Height	~50 cm (sources say 40–50)
Weight	~2.8 kg
Compute	Raspberry Pi 4B (later Z-Bot); Milk-V Duo S (early Zeroth-01)
Speed	0.35 m/s (old site claim, unverified)
DOF	18–20 Feetech STS3215/STS3250
Sensors	BNO055 IMU, wide-angle camera, mic/speaker
Balance	RL policies trained in MuJoCo via K-Scale's ksim (JAX/MJX); walking was "public alpha" and there is no push-recovery data.
SDK	kos-zbot, ksim-gym-zbot, kinfer (GitHub); docs site offline