The Bosch GLL25-10 Self-Leveling Cross-Line Laser projects two lines, making a cross-line projection, for a wide array of level and alignment applications. The lines are precisely level and plumb, for easy, accurate layout. The laser lines are visible up to 30 feet and offer accuracy of +/-5/16 inch at 30 feet. The Smart Pendulum System self-levels and indicates out-of-level condition to help ensure an accurate layout. The pendulum system locks when switched off, to assure secure tool transport. The included MM 2 Flexible Mounting Device provides a rotating 360 degree neck for quick setup and simple fine-tuning. This mount allows the laser to be clamped on virtually any surface from 1/2 to 2-1/4 inches thick.