1. Taking a measurement - Press MEASURE to turn on the unit. The measurer beeps then the distance between the measurer and the point you measured appears. - Hold the bottom of the measurer flat against a wall, about halfway between the floor and ceiling. Be sure there is a clear path to the point you want to measure and that your head or hands do not block the front of the measurer. - Repeatedly press FEET/METER until FEET appears (to measure in feet ) or until METER appears (to measure in meter). - Press and hold down MEASURE to take a continuous measurement 2. Stabilizing the measure - Your measurer is sensitive to changes in temperature and humidity. Before you use the measurer, wait about 15~30 minutes for it to stabilize to the current rooma is temperature. 3. Measuring Tips - Some types of curtains and blinds can absorb sound waves, causing measurements to be inaccurate. If you are measuring distances in a room with curtains, open the curtains before measuring the distance to a window behind them. Also, be sure that the window is closed. - If there is not a clear path between the points where you are measuring, you might receive a false reading from sound waves bouncing off objects such as chairs, tables and objects with uneven surfaces. If you are not sure if a measurement is correct, move slightly to one side then measure the distance again. - If the surface of a wall you are measuring is not solid and flat, of if you are measuring in a narrow corridor, you might receive a false reading. If this happens, use a solid surface to measure or move to the center of the corridor. - To measure a distance longer than 60 feet (18.288meters), select a point in the middle of the room (for example), measure from the center of the room toward each side, then add the two measurements. 4. Calculating volume - To find the volume of a room, measure the height, width and the length of the room and store each measurement in a different memory location (see "Saving a Measurement"). Then press VOLUME, the volume calculation result appear. 5. Power Source: 1 x 9V battery(not included)Specification: Package Weight One Package Weight 0.18kgs / 0.40lb Qty per Carton 24 Carton Weight 4.60kgs / 10.14lb Carton Size 46cm * 35cm * 35cm / 18.11inch * 13.78inch * 13.78inch Loading Container 20GP: 473 cartons * 24 pcs = 11352 pcs40HQ: 1098 cartons * 24 pcs = 26352 pcs