The 20mm general gearmotors are widely used on Intelligent robots,intelligent manipulators, intelligent furnitures, Intelligent focusing systems etc. Those are incredibly tough and feature full metal gears. Have gear ratio 12.5:1 to 488:1, 780rpm~20rpm, stall torque 0.7~6Kg.cmType: MG20B-120020-488Features:
Voltage: 6-12 Volts
Gear Ratio: 488:1
Stall Torque:6.0kg.cm (12V)
No load Speed: 20RPM (12V)
No Load Current: 160mA (12V)
Rated: 5Kg.cm,15rpm,550mA
Stall Current: 2.5A (12V)(data sheet at: 12V 780rpm 12.5:1 )