The laser level adopt gravity pendulum, can self-leveling. Lock function- Keep the button in ''OFF'' position, pendulum is locked during transporting or not working. Slope mode- Keep the button in ''OFF'' position, press the power button, the laser beam will flash slowly. Strong design with glass enclosed cage for better protection and water/dust resistance (IP54) It is a great option when hanging pictures, wall ornaments, wall stickers, placing electrical wiring conduits, as a guide for suspended ceilings.