Varex Canbus compatible and Hard wiring harness High quality Canbus vehicle compatible wiring harness for the Varex Smartbox system. This harness draws power directly from the vehicle battery and is switched on and off via an included relay to ignition power. The Varex Canbus compatible wiring harness can be used on some vehicles were the addition of an external power draw can create challenges or issues, this harness allows complete function of the Varex Smartbox system and works in synergy with the vehicles Canbus system and BCM/ECU. This can be used in all vehicles with Varex should you wish to have a nice and tidy hidden wiring kit that doesn't occupy the 12V power socket.