Two servo-linear-motors (hybrid, custom made by a company)
- accept PWM signals with 16bit of precision on a 2msec pulse
- controller by a digital controller with position feedback
- able to pull/push up to 500N!!! (~50Kg!!!)
- only 500mA of stall current!!!
- 6V powered
- gear-ratio 1:1000 reduction (yes, it's *VERY* slow)
- alluminium metal case with steel reinforcements
cost me ... a lot: only 90 euro each, but they only have 2 units and it's out of production