The DEWALT DWHT77100 Laser Distance Measure calculates distance in metric and imperial measurements. It can also be used for Area, Volume and Pythagoras calculations. It has a compact, lightweight design for easy storage/transportation. Fitted with a TPE overmould for a secure grip and slip protection. There is also a lanyard loop hole for attachment to lanyards/hand-loops to prevent accidental drop. Specification: Accuracy: ± 3mm per 10m Range: 30m Power: 2 x AAA batteries (supplied).