1) Detection range: 0.3 - 2.19m behind the car 2) Power voltage: 10V-15V DC 3) Alarm volume: >78dB 4) Operative temperature: -40-80oC 5) The system will automatically detect obstacles behind the car when in reverse gear 6) Accurately senses obstacles via 60 degrees "cone of detection" from each sensor 7) The buzzer has three different tone levels to warn of object proximity 8) Various sensor colors such as black, grey, blue, red, green, and white are available 9) 2 - 8 sensors are available 10) LCD display options 11) Full DIY instruction makes system easy to install Inner packing: 1 set/gift box Box dimensions: 23 x 17 x 4cm Outer packing: 20 sets/carton