Bosch GLL50-20 Self-Leveling Cross-Line Laser features a 50 Ft. range and cross-line mode that projects both horizontal and vertical red lines, allowing for leveling with a 5/16 In. accuracy at 30 Ft. With its power flexibility, operate using the included AA batteries or purchase, Bosch's 3.7V Lithium-Ion 1.0 Ah Battery (Sold Separately) that allows use of the tool while charging to diminish downtime. Its ergonomic, compact, lightweight design and IP 55 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 for safeguarding. 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. Simply tilt the laser to use the lines at an angle with ease.