safemate wireless display and the waterproof controller are much easier to install than any other backup systems. The wireless LCD display shows the barrier distance (in ft) from the bumper (up to 8ft (2.4m)) and the orientation, and the speaker sounds long intermittent beeps. As the rear of the car moves closer to the barriers, the beep increases in frequency. Once the distance is 1ft (0.3m) or less, the alert becomes a continuous sound.