"The Bosch GLL 30 Self-Leveling Cross-Line Laser projects two lines, making a cross-line projection, for a wide array of level and align uses. This versatility makes it more valuable than a typical line laser. With top-notch accuracy and one-switch operation, the user's leveling and alignment tasks are done quickly and correctly. The laser lines are visible up to 30 Ft. 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 microfine height adjustment, and it allows the laser to be clamped on virtually any surface from 1/2 In. to 2-1/4 In. thick, for level lines at any height"--