Features:
Automatically activated when reversing gear is engaged
The closer the obstacle is, the faster the alert beeping frequency is to indicate the safety zone,
caution zone and danger zone
2/4/6/8 ultrasonic sensors selectable 
Voice report optional
Purple background screen
Ajustable volume: HI/LO/OFF
Dynamic digital LCD display to indicate differentdistances as well as orientation of the obstacle (front or back)
Dynamic sketch indicater of the working sensors
Exact distance display STOP reminder 

Technical Parameters: 
Operating voltage: 12V DC (24V optional)  
Operation current: 20mAh ~ 200mAh 
Sensor installation height: 45 ~ 60cm 
Detection distance: 0.2 ~ 2.0m 
Ultrasonic frequency: 40kHz 
Operating temperature: -40°C ~ +85°C 
Beep volume: 80 ~ 100dB (at 30cm distance)