When the knob is pushed in, the switch is off. Pull the knob out one position, and the park & tail lights are on. Pull the knob out one more position and the low beams and tail lights are on. Pull the knob out all the way and the tail lights and high beams are on. Requires external circuit protection. Complete instructions included. Requires a 3/8" mounting hole. Includes matching Synergy Series knob, bezel & accent ring.