The Stage 4 kit is the complete package that combines the Stage 3 kit with our rear speaker option. Adding our RM1 series mini speaker enclosure and clamp system, this kit adds the last bit of sound that you need. Simply plug in the harness, mount the speakers and rock out. Whether hitting the dunes or the trails, you are sure to be the center of attention of any get-together. Compatible with factory equipped Smart-Lok module.