-The CST/Berger 57-LMH600D Electronic Self Leveling Horizontal/Vertical Dual Beam Rotary Laser Level with Dual Manual Grade offers fast and simple leveling power to handle your toughest jobs with less manpower.-Levels itself horizontally and vertically via electronic sensors interfaced with motors and precision software eliminating the need for re-leveling or rechecks.-The Anti-Drift System, or height of instrument alert, warning the operator that the instrument has been moved.-Achieves an accuracy of 1/16 at 100ft and has a working range of up to 2000ft in diameter when used with the included laser detector.-The laser has a self leveling range of /-5 degrees (horizontal and vertical) which takes the guess work out of setting up the instrument. Just make sure that the level is laid on its side or on a tripod head that is generally level, and turn it on, the 57-LMH600D takes care of the rest.-The laser level has variable rotation speeds of 0, 150, 300 and 600RPM which makes the 57-LMH600D laser level useful for not only general leveling with the detector and rod, but also when needing to project visible laser lines or chalk lines on walls, floors or surfaces.-Adjustable Laser Chalk lines, Clockwise and Counter Clockwise beam positioning, Dual Manual Grade up to /-10% in both axis.-Auto Beam Positioning system that positions the laser dot in a plumb down position when being used in the vertical mode allowing you to precisely position the 57-LMH600D laser level over a reference point or mark.-Powered by 4 D batteries powering the unit for up to 75 hours. -Enclosed and sealed laser beacon that enables the unit to be used in almost all weather conditions.