This is a opitonal RPM Rear Hub Carrier Set, and is intended for use with all vehicles that use the ASC9730 hub carrier. RPM steps up to deliver a superior axle carrier design while using the larger outer bearings found in Associated’s #9730 axle carriers. The larger outer bearing supports the axle better, providing over 1/16” more axle contact than two 3/16” x 3/8” standard bearings, for smoother, longer lasting performance. With the larger outer bearing and RPM proprietary materials, you get the perfect blend of strength and durability for a whole range of Associated 1/10th scale electric vehicles! RPM axle carriers are molded in black and factory-backed by RPM's industry-leading warranty program and are proudly manufactured in the USA!