This gearmotor comes pre-assembled, with the gears fully enclosed. There are built-in mounting holes, and the output shaft is 7 mm in diameter with two sides flattened.

• Voltage: 12V Dc 
• RPM: 200
• Torque: 43oz.in (3.096 kg-cm)
• Current: 57.6mA
• Reduction: 1:87
• Shaft length: 7mm double-flat
• Size: 55x48x23 mm
• Weight: 32grams (1.13oz)

The  Gear Motor is much like the BO1 gear motor but runs at nearly twice the speed. This 87:1 gear motor spins at 200RPM at 12V, drawing 700mA at stall generating 43 in.oz torque (free running at 57.6mA). With a 7mm double-flat output shaft (avoid using the WHITE double flat output - it's not meant to take rotational load), and a built-in clutch and built-in mounting screw holes, you can see why we like these motors! These fit perfectly with BO  TYRE plastic wheels.