120:1 Mini Plastic Gearmotor HP, Offset 3mm D-Shaft Output, with 12 CPR Encoder, Back Connector

This small gearmotor features a brushed DC motor with a 120:1 plastic gearbox and a quadrature encoder with back connector (cables sold separately). While intended for operation at 4.5 V, it runs comfortably in the 3 V to 6 V range. The gearbox has a 9.7 mm long, 3 mm diameter D-shaped output shaft, and a built-in safety clutch helps protect the gears from excessive loads.