This cylindrical, 1.89" x 0.98" x 0.98" gearmotor uses a motor with extra-strong magnets and a 9.7:1 metal gearbox to deliver a lot of power in a relatively small package. This unit has a 0.315"-long, 4 mm-diameter D-shaped output shaft. Key specs at 6 V: 1010 RPM and 450 mA free-run, 17 oz-in (1.2 kg-cm) and 6 A stall. This motor is intended for use at 6 V. In general, this kind of motors can run at voltages above and below this nominal voltage, so they should comfortably operate in the 3 – 9 V range, though they can begin rotating at voltages as low as 1 V. Higher voltages could start negatively affecting the life of the motor. Metal Gearmotor Comparison Table atio No-LoadSpeed@ 6 V Stall Torque@ 6 V Stall Current@ 6 V With Encoder Without Encoder 1:1 9800 RPM 2 oz-in 6 A motor without gearbox 5600 RPM 1 oz-in 2.2 A motor without gearbox 4.4:1 2220 RPM 8 oz-in 6 A 25Dx48L mm HP 1280 RPM 5 oz-in 2.2 A 25Dx48L mm 9.7:1 1010 RPM 17 oz-in 6 A 25Dx48L mm HP 25Dx48L mm HP 580 RPM 11 oz-in 2.2 A 25Dx48L mm 25Dx48L mm 20.4:1 480 RPM 36 oz-in 6 A 25Dx50L mm HP 275 RPM 24 oz-in 2.2 A 25Dx50L mm 34:1 285 RPM 60 oz-in 6 A 25Dx52L mm HP 25Dx52L mm HP 165 RPM 40 oz-in 2.2 A 25Dx52L mm 25Dx52L mm 47:1 210 RPM 80 oz-in 6 A 25Dx52L mm HP 25Dx52L mm HP 120 RPM 50 oz-in 2.2 A 25Dx52L mm 25Dx52L mm 75:1 130 RPM 130 oz-in 6 A 25Dx54L mm HP 25Dx54L mm HP 75 RPM 85 oz-in 2.2 A 25Dx54L mm 25Dx54L mm 99:1 100 RPM 160 oz-in 6 A 25Dx54L mm HP 57 RPM 110 oz-in 2.2 A 25Dx54L mm 172:1 57 RPM 260 oz-in 6 A 25Dx56L mm HP 33 RPM 170 oz-in 2.2 A 25Dx56L mm 25Dx56L mm 227:1 25 RPM 220 oz-in 2.2 A 25Dx56L mm 378:1 15 RPM 250 oz-in 2.2 A 25Dx58L mm 499:1 12 RPM 300 oz-in 2.2 A 25Dx58L mm