1.automatically engages
2.Show distance by LED lamp/LED display, BiBi voice warning.
3.Embedded detector sensors
4.Easy installation.
5.Speaker is embeded in the display housing.

Specification
1. System detecting obstacle using Ultrasonic Wave Echolocation Technology 
2. Wireless LED Digital Display with Built-in Audible Alert (Beeper). 
3. Easy Installation NO wire connection between main box and LED Display
4. Speaker warning can optional
5. Sensor Detection Range: 0.3m - 2m 
6. 4 rear sensors giving good coverage of the rear end of your vehicle when backing up 
7. Each sensor with wedge-shaped plastic spacer for adjusting to non-vertical bumper surface 
8. Perfect for backing up, street parking, parallel parking, garage parking, and parking in tight spot ... 
9. Powered by tapping into the wires of back up light 
10. Activated when vehicle is put in reverse 
11. High Quality 
12. Competitive Prices 
13. 12 months warranty 

Instruction
1. Rated voltage: DC12V
2. Operating range: DC10V~15V
3. Power: 4W
4. Detecting distance: 1.5M~0.3M
5. Detecting angle: H>60 degree, V>60 degree
6. Microphone sensitivity: >=73dB
7. Speaker power: 8 ohm, 0.5W

Package contents:
4 x Ultrasonic Sensor
1 x Control Box/Unit
1 x Mini LED Display
1 x Power cable
1 x Drill /Hole Saw
1 x User manual