... active wheel device, the transmission mechanism, polishing speed regulation control mechanism composition.1, high strength ... , no both recoil.2, variable speed range: variable speed range for 5, namely tachometer output ... and 45 to any change.3, speed high precision: speed precision for 0.5-1 turn ... with various types deceleration unit close, realizing low speed, big twist compasses change-up effect, has ...