The distance meter is a measuring tool used to measure the straight distance. It is an advance ultrasonic measurement system. The distance meter will reckon the distance between the meter and obstacle according to the time the sound waves to return to the meter system. Whats more, the meter will convert the measurement value into Britain system or metric systems and display it in the display window of the meter. The temperature will influence the speed of sound wave, but the meter has an auto temperature compensation function. T herefore, it can make a precise measurement at the ambient temperature. Specification: 1. Range:0.9-12m/3-40Ft 2. Accuracy :+--0.5%+1digit 3. Meter / feet conversion 4. Auto power off 5. Low battery indication 6. Battery: Heavy Duty 6F22ND 9VDC 7. Laser wavelength/power: 650nm/ 1mw 8. Laser Hazard Classes: class II 9. CE Certified 10. Several colors choices: Red, yellow, green, blue