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 GM9gearboxes and the larger Pololu plastic gearmotors. The track links and pins are sold separately.

These 8-tooth, injection-molded sprockets are made to work with the rugged miniature tank tracks. This set comes with four sprockets made from sturdy, black ABS plastic: two sprockets for mounting on the 7-mm shafts of 228:1 offset, 120:1 offset, 200:1 90-degree, and 120:1 90-degree pololu plastic gearmotors or Solarbotics GM2, GM3, GM8, and GM9 gearboxes, and two idler sprockets with 1/4? holes that you can mount using shoulder bolts.

The diameter of the sprocket by itself is 1.5?. Once the rugged miniature tank tracks are around the sprocket, the total diameter is roughly 1.77?.

18-link chains of the miniature tank tracks in assorted colors with 8-tooth sprocket pairs.