36xx and 40xx series dual extreme fans. These fit all 36mm motors both finned and smooth can as well as SMOOTH can 40xx series motors. Obvious desired uses are Arrma Limitless / Infraction 40xx TP motors, Leopard 40xx motors etc. These fans can be run off the receiver as they come with standard JR lead which plugs into an open receiver port, as well as an On/off switch adapter which has 4s balance tap lead on the other end for EXTREME cooling. This is IDEAL for the speed run folks who are looking to run a separate small 4s lipo which we do carry here at WFO as well.