LL300N Laser Specifications; Laser Source: 650 nm, Class 2, <3,4mW; Laser Accuracy: 3/32 in at 100 ft ( 2.2 mm at 30 m); Operating Range: 1,650 ft (500 m) diameter; Self-leveling Range: 5 degrees; Compensation Method: Electronic self-leveling; Drop Height on Concrete Performance: 3 ft (1 m); Single Axis Manual Slope Mode: Yes (w/self-leveling mode on the second axis), with optional RC601 remote control (included); Out-of-level Warning: Rotor stops, red out-of-level HI-LED flashes; Power Source: 4 x D-cell NiMH or alkaline batteries; Battery Life: Rechargeable - 45 hours, Alkaline - 90 hours; Battery Status LED: Flashing red LED