Features: Ultrasonic range finder is fully applicable to home decoration, buy air conditioning calculation area of volume, real estate agents or construction workers must, need fast measurement tool room and room area, ultrasonic range finder capable of measuring linear distance from 0.50M to 18M. (1.5 feet -60 feet) is the use of ultrasonic waves ultrasonic distance to the object, and then calculate the round trip time ultrasound to determine the measurement distance. s: LCD display, easy to read and use. Lightweight and easy for you to carry. Specifications: Measuring range: 50 cm to 18 m Resolution: 0.01 m Maximum measurement distance: 18 meters And the maximum distance: 180.00 m And the maximum distance: 180.00 m Maximum volume calculation: 1800.0 cubic meters Power: 9v battery Transmission frequency: 40kHz Operating temperature: 0 C ~ 43 C Size; approx 15x 5x 3cm Color: red Rangefinder Instructions: Warning: If you are not more than a month or a month, please remove the battery to avoid battery long time without leakage damaged instruments. Usage: Rangefinder switches: To open this instrument, please press & 39;& 39;MEASURER& 39;& 39; Even in the dim light can easily display screen. 30 seconds if you do not shut down automatically. Measurements: 1. Click on the & 39;& 39;MEASURE& 39;& 39;, this instrument will measure radar instrument reaches the other end to be measured. 2. Make the bottom of the instrument close to the wall, probably from the ceiling to the floor. Make sure there are no obstacles between you measure the distance, your head or your hands do not in front of the measurement instrument. 3. Repeat Press & 39;& 39;FEET& 39;& 39; or & 39;& 39;METER& 39;& 39;, & 39;& 39;FEET& 39;& 39; expressed in feet measured, or the emergence of "METER" indicates measured in meters. Explanation: Meter display is generally about 30 seconds, if you change to another mode is about 30 seconds. If you measure a range of less than 2 feet (0.5 meters) or greater than 60 feet (18.288 meters) will show "ERROR" Measurement tips: Some curtain can absorb sound waves, resulting in Measurement are not allowed. If you have curtains indoor measurements, please first the curtain into the window on the other side, but also to close the window. If there is an obstacle in the distance measurement, then the ultrasonic measured data is incorrect, for example tables, chairs, or other obstructions. If you are not sure you are measuring is correct, then you make multiple measurements from different angles. If it is not where you are measuring flat or very narrow corner, then you come to the data that is in error. If you want to measure a distance greater than 60 feet (18.288 meters) then choose the house in the middle of the point, for example: measuring from point to each side, then add it. Package Includes: 1 x Distance measurer