... Bi voice prompts at three levels> To show to the rear 4 sensors> Sensors color optional Sensor waterproof, shockproof, high temperature ... proof connector sensors > install 4 water-proof connector sensors in rear,easily install anytime.2) Flash Sensors "> Driving at night to ... , flashing blue light-emittingsensors,to remind the car to avoid rear-end collision, at the same time addstyle; Or reverse, the ...