RE: can someone help me????
REC is the reciever. Instead of the ESC connecting directly to the reciever, it will connect to the cutoff and the cutoff will connect to the receiver. This is so that when the cutoff detects the low voltage in the packs it will cut the throttle. There is no cutoff that will work with your truck with no modification unless you went brushless, in which case the ESC would have it built in.