Park your vehicle perfectly every time! The Park-Zone works like a traffic light to tell you that your vehicle is parked in the correct spot. Just hang Park-Zone on the rear wall of the garage; the ultrasonic sensor will tell you when to approach and when to stop. No ifs, ands, or bumps! The Park-Zone helps the depth perception impaired to park in the same spot every time, without pulling too close to the wall or not close enough. If you?ve ever had that moment of panic that you left the rear of the car sticking out too far as the garage door closes, the Park-Zone will eliminate that concern. You?ll park just right every time. The Park-Zone consists of 3 parts: an ultrasonic sensor, a ?traffic? light, and an AC adapter. The ultrasonic sensor hangs at bumper level and communicates with the Park-Zone light, which hangs at eye level. The sensor indicates to the light the distance between itself and your vehicle?s bumper. When you?re approaching, the Park-Zone light is green. When you?re about halfway there, the light turns yellow. When the light turns red, stop. You?ll be parked at the perfect distance from the wall. The Park-Zone will work for about a year on 4 AA batteries, but an AC adapter is included for your convenience. The Park-Zone is programmable to your parking preference. The range of the ultrasonic sensor is from 1.3- 16 ft. Whether you have garage that?s 20 ft. deep or a real showroom, the Park-Zone will help you park in the same spot every time. Park in the perfect spot every time you enter the garage with the Park-Zone. AC adapter included/ DC battery backup power.