This is a fan shroud for two 40mm fans that will fit the Traxxas XRT, X-Maxx, and some Arrma vehicles and probably others. It's designed for big motors like the Castle 2028 and Hobbywing 56118 but will fit any 56mm motor that has 85mm of length for the shroud to mount. It attaches with zip ties directly to the motor and shrouds the motor to direct air flow over the motor's heat sink fins!