1.28mm planetary gearbox,Double the shaft. 19:1. 2.Can allocate deceleration than 3.A variety of outer diameter to choose from 1.28mm planetary gearbox,Double the shaft. 19:1.2.Can allocate deceleration than3.A variety of outer diameter to choose from4.plnaetary gear box,Can be equipped with dc motor, brushless motor, stepping motor 28mm planetary gearbox with dc motor of GMP28