Spectra Precision Lasers / Trimble GL612 Single-Slope Grade Laser with Hl750 Laserometer, Rod Clamp, Rc602 Remote, 10 Ah Nimh Batteries and Charger Automatic self-leveling provides fast, easy horizontal level, grade and vertical plumb setup and a large compensated grade range from 25% No rework due to automatic temperature and grade - and cross axis compensation Very rugged, survives a 1 m (3 ft.) drop on concrete - reduces service and repair costs even with a 5 year limited repair warranty Automatic Grade Match measures and displays the existing grade over unknown ground and eliminates time consuming and error prone calculations Automatic PlaneLok automatically locks on to an existing elevation or vertical alignment point which eliminates all drift or possibility of error Class 2 Laser and &lt;3mW (less than 3 Milliwatts)