Features: 1) Display type: LED, wave band, buzzer, digital 2) Sensor number: 2 and 4 pieces 3) Sensor color: marine blue, white, urban grey, yellow, green jade, red, diamond blue, titanium grey, black 4) Detector type: drilling or adhesive 5) Automatically starts after turning on the power 6) Ultrasonic detecting-head design to measure accurately, quality guarantee 7) Accurate and reliable US super misinformation proof technology