The Bosch GLL50-20GL Green-Beam Self-Leveling Cross-Line Laser projects two level and plumb green beams that are up to 4X brighter than standard red beams. Featuring a 65 Ft. range that allows for leveling within a 1/4 In. accuracy at 30 Ft., its a must-have for any tool bag. With its power flexibility, operate using the included Bosch 3.7V Lithium-Ion 1.0 Ah Battery that can even be used while charging to diminish downtime or with two AA batteries (sold separately). Built-in VisiMax technology optimizes line visibility and runtime for working conditions to further maximize usage. Its ergonomic, compact, lightweight design and IP55 dust- and water-resistant rating, provide for both comfortable and dependable operation. The full rubber overmold housing helps protect every major impact point, acting like a roll cage to safeguard the tool. Equipped with a Smart Pendulum System, the tool self levels, will indicate any out-of-level condition by blinking and then locks when switched off for secure transport