This gearmotor is a powerful brushed DC motor with 131.25:1 metal gearbox intended for operation at 12 V. The gearbox is composed mainly of spur gears, but it features helical gears for the first stage for reduced noise and improved efficiency. These units have a 16 mm-long, 6 mm-diameter D-shaped output shaft. Key specifications: voltage no-load performance stall extrapolation 12 V 76 RPM, 150 mA 45 kg⋅cm (630 oz⋅in), 5.5 A Dimensions Dimensions of the 37D mm metal gearmotor (without encoder). Units are mm over [inches]. Dimensions Size: 37D × 57L mm1 Weight: 195 g Shaft diameter: 6 mm2 General specifications Gear ratio: 131.25:1 No-load speed @ 12V: 76 rpm No-load current @ 12V: 0.15 A Stall current @ 12V: 5.5 A3 Stall torque @ 12V: 45 kg·cm3 Max output power @ 12V: 6 W4 No-load speed @ 6V: 38 rpm5 No-load current @ 6V: 0.1 A5 Stall current @ 6V: 3.0 A5 Stall torque @ 6V: 28 kg·cm5 Performance at maximum efficiency Max efficiency @ 12V: 45 % Speed at max efficiency: 66 rpm Torque at max efficiency: 6.0 kg·cm Current at max efficiency: 0.74 A Output power at max efficiency: 4.1 W General specifications Encoders?: N Notes: 1: Length measurement is from gearbox face plate to back of motor (it does not include the output shaft or motor terminals). See dimension diagram for details. 2: D shaft. 3: Stalling is likely to damage the gearmotor. Stall parameters come from a theoretical extrapolation of performance at loads far from stall. As the motor heats up, as happens as it approaches an actual stall, the stall torque and current decrease. 4:This is the output power at the maximum recommended operating load of 10 kg⋅cm; higher power might be achievable for brief durations at higher loads (see performance graphs in the datasheet). 5: This motor will run at 6 V but is intended for operation at 12 V.