Pololu 47:1 Metal Gearmotor 25Dx52L mm LP 6V with 48 CPR Encoder This gearmotor consists of alow-power, 6Vbrushed DC motor combined with a46.85:1metal spur gearbox, and it has an integrated 48CPR quadrature encoder on the motor shaft, which provides2248.86 counts per revolutionof the gearboxs output shaft The gearmotor is cylindrical, with a diameter just under 25mm, and the D-shaped output shaft is 4mm in diameter and extends 12.5mm from the face plate of the gearbox Key specs at 6V:120RPM and 250mA free-run, 65oz-in (4.7kg-cm) and 2.4A stall