This gearmotor is a powerful 12V brushed DC motor with a 131.25:1 metal gearbox and an integrated quadrature encoder that provides a resolution of 64 counts per revolution of the motor shaft, which corresponds to 8400 counts per revolution of the gearbox’s output shaft. These units have a 0.61"-long, 6 mm-diameter D-shaped output shaft. This gearmotor is also available without an encoder.
Key specs at 12 V: 80 RPM and 300 mA free-run, 250 oz-in (18 kg-cm) and 5 A stall.
These motors are intended for use at 12 V, though in general, these kinds of motors can run at voltages above and below the nominal voltage (they can begin rotating at voltages as low as 1 V). Lower voltages might not be practical, and higher voltages could start negatively affecting the life of the motor.
This diagram is also available as a downloadable PDF (277k pdf).