1、WORKING PRINCIPLE It is used to transmit ultrasonic waves to the measured object, and then calculate the ultrasonic round trip time to determine the measurement distance. 2、MULTIPURPOSE It is suitable for home decoration, calculation of area and volume when buying air conditioners, property agents or construction workers who need to quickly measure the area of ​​rooms and rooms. 3、WIDE RANGE OF APPLICATION It is very suitable for indoor and outdoor surveying, building surveying, woodworking surveying, interior decoration and so on. 4、CLEAR MEMORY FUNCTION This function allows you to quickly delete all stored measurement values, and the operation is simple and quick. 5、EASY TO CARRY With its small size and light weight, it can be comfortably placed in your hand and easily placed in your pocket. Item Type: Range Finder Material: ABS Weight: Approx. 105g / 3.7oz Product Size: Approx. 15x5.5x3cm / 5.9x2.2x1.2in Battery Parameter: 1 x 9V Battery (Battery Not Included) Measuring Range: Approx. 0.5~18m / 1.6-59.1ft Error: Five Thousandths Resolution: 0.01m Maximum Measuring Distance: Approx. 18m / 59.1ft Maximum Sum of Distances: Approx. 180m / 590.6ft Maximum Calculated Volume: 1800.0 Cubic Meters Transmission Frequency: 40kHz Working Temperature: 0°C ~ 43°C 1 x Range Finder (Battery Not Included) 1 x English Manual