The SmartTool digital level is a durable field tool that can be used as a level, plumb and clinometer. It digitally displays angles in degrees, percent slope and pitch (inches of rise or fall per linear foot) to an accuracy of 1/10 degree.This unit is designed to sit on a surface and measure the slope of that surface. It is not designed to sight on a distant object and measure the slope to that object.Controls include: ON/OFF - automatic shut-off if left idle for 6 minutes HOLD - freeze or unfreeze display readings LISTEN & LEVEL AUDIO - beeper will sound at level and plumb CALIBRATE - simple two-step calibration procedure (recommended once per day) Deg.,%,IN/FT - select display units UP/DOWN ARROWS - show direction of tilt to reach level or plumb LOW BATTERY - low 9V battery indicator Dimensions are 6" x 1 1/2" x 2". Weight 7 1/2 oz. Housed in environmentally sealed polycarbonate housing. 9 volt battery provides up to 120 hours of continuous use.