* reverse sensor, mirror VFD display * display back with switch for voice ON/OFF * Bi-Bi-Bi; BiBiBi; Biii 3 stages voice alerting * Waterproof and shockproof ultrasonic sensor * Special 2 angles sensor, horizontal & vertical detection * 2, 4, 6 or 8 sensor available, and human voice speaking for choice * 1 year warranty at least Technical Details: Working voltage: 12V DC +/-2V Maximum power: <5W Working temperature: -40 to +80deg. C Beeper: 60-105dB(adjustable