This four-pack of 8-tooth injection-molded sprockets comes with two idler sprockets (with 1/4" holes) and two sprockets with 7-mm holes for use with for use with Solarbotics GM2, GM3, GM8, and GM9 gearboxes. They are ideal for use with our Tank Track kit and Shoulder Bolt idler axis.

***Please note : In the image the idler sprockets are the wheel shaped items*** The sprockets do not come supplied with tracks, motor/gearboxes.