... -12V 2.Speed&Torque :10-2000RPM,1:10 to 1:1000 Ratio 3. Stall torque high to 5kg.cm 4. Metal gea for robot ... , toy gear motor 6V:Application inRobot,Automatic Door Lock, ToysReduction Ratio 1:10,1:20,1 ... :Don't hesitate to contact with me if any more questions.. 6v 12mm diameter 1:10 to 1:1000 ratio 10 to 3000rpm micro metal ...