The BackOFF XP module works with a center dedicated brake light, but can also work on multiple brake lights (up to 10AMP, or up to three (3) standard 1156/1157 incandescent bulbs). The BackOFF Wig Wag module is meant for a pair (2) brake lights that are dedicated brake lights on (the brake lights can be running lights, BUT they CANNOT be a combination brake light/turn signal light setup). The BackOFF Wig Wag is not typically used on just a single center dedicated brake light, and we would always recommend the BackOFF XP module for a single center dedicated brake light.