It's a perfect tool to quickly know the distance， area and volume of a roomWith laser point aiming to see the target that one wishes to measure distance. The ULTRASONIC DISTANCE METER LASER POINTER is a perfect tool to quickly know the distance， area and volume of a room! It can measure distances in a straight-line from 1.5 feet o 60 feet. Your distance measurer transmits ultrasonic waves to a point you want to measure. Afterwards， it measures the time taken by the waves to reflect and then calculates and re-transcribes the distance.LCD with Backlight.Power supply: 1 x 9v Alkaline Battery (battery not included)Measure Distance From 2 Feet to 60 Feet.( About 0.8 to 18 meters)Area， volume， addition， subtraction calculation.Frequency: 40kHz (ultrasonic pickup)Resolution 0.01M or 1/2 Inch.Working temperature 32 F to 109.4 F ( 0 'C to 43 'C)Accuracy:+/- 0.5%25 +/-1Auto OFF: switches off if you do not press any key for about 1 min.Your distance measurer transmits ultrasonic waves to a point you want to measure. It measures the time taken by the waves to reflect and then calculates and re-transcribes the distance.Units of Measure : Feet/Meters Caution: Don't stare into the laser beam and also don't shoot laser beam to any other's eyes.The Laser emitted from the unit is visible laser of 650mm wavelength. Package Include:1 x Ultrasonic Distance Measurer (NO battery)1 x English Manual