This ball bearing set is designed to be used for the TT-02 chassis platform. It replaces all plastic bushings with ball bearings resulting in a more efficient drive-train enabling faster speeds and higher durability. Can be used in conjunction with the new TT-02 chassis. 1050 Ball bearings x8 1150 Ball bearings x4 1280 Ball bearings x4 Note: This complete ball bearing set is not for use on the TT-02B Buggy Chassis.