These are just amazing little motors for their weight. With one at each of your four corners you are always guaranteed good traction and speed. These have a special long shaft with a "D" cut into it for the outer 10mm to ensure full engagement and proper spacing of our tank tread wheels.

Specs:
5-14v
18mm long shaft x 3mm diameter
D shape on last 10mm
100:1 gear ratio
Size 0.47" x 0.39" x 1.24"
Weight 8.5 grams (0.31 oz)

SRV-1 Surveyor Robot

SRV Tank Tread Set

SRV Drive Base Kit