This harness is designed as a frill-less option for undercover vehicles that don't include significant vehicle modifications. It does not require a SoundOff Signal Control Panel. Instead, it includes a 4-way progressive rotary switch intended for use as Level 1, Level 2, Level 3, Level 3 + siren inputs to the siren system, but you can program them as you need. The kit includes a housing and status LED for the switch, mountable in any location.