The 25mm 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 4.4:1 to 478:1,2700rpm~25rpm, stall torque 1.8~12Kg.cm
Type: MG25B-120600-20
Features:
Voltage: 6-12 Volts
Gear Ratio: 20:1
Stall Torque:7Kg.cm (12V)
No load Speed: 600RPM (12V)
No Load Current: 200mA (12V)
Rated: 3.5Kg.cm,350rpm,1.5A
Stall Current: 5.6A (12V)
(data sheet at: 12V 600rpm 20:1 )