This 7 inch Rearview Mirror Monitor has 3 AV inputs which can be connected up to 3 reversing cameras. This system also comes with 3 trigger wires for cameras. Once a trigger wire is activated, for example, when the reverse gear is induced it will show the rearview automatically. Or when the vehicle is put on the turn Right signal the monitor will switch to the Right camera automatically to give clear view on the right side of vehicle before making a turn. This Rearview Mirror Monitor is suitable for 12V/24V vehicles including buses, cars, trucks and caravans. Please note that this comes with one 7 inch LCD Monitor only, no cameras and cables are included.