The unique feature of lomvum laser digital protractor is the two side laser design. You can turn on both lasers on the left and right side when doing the measuring, which make the measurement more accurate. Lomvum laser digital protractor is pocket- size and lightweight. When the inclinometer is turned upside down, the angle reading on the lcd will automatically flip up and easy to be read. Lomvum laser digital protractor is usb rechargeable. We adopted 3.7v 300mah lithium battery which is eco- friendly and recyclable. You can charge the inclinometer with a usb cable at anytime. To save the power, the inclinometer will shut- down in 5 minutes automatically. Magnet designed allows lomvum laser digital protractor to be attached to any metal surface. 360 degrees angle measurement or slope measurement in 4 directions. Lomvum digital angle tool can measure in absolute and relative measurements for determining the exact angle or the difference between 2 angles. Ip54 waterproof protection challenge any working environment. Package includes 1 x gr20 laser protractor.