HUADER line laser takes advanced technology to deliver brighter green line laser high visibility and the most precisest results. 3 Measurement Modes - Laser level tool gives more choices for your projects; and avoid from being inclined.Widely Applications - The lazer line level designed for picture hanging, construction, writing, wall/floor tiling, home rennovation and window/door installation. Good for building, ceiling, basement, etc.High Accuracy & Low Consumption - This level tool with high accuracy and low comsumption, its error range is ±4°, it would be a great help to your projects. HUADER Green Cross Laser Level with 3 Modes: UNLOCK "PENDULUM" Equipped with intelligent pendulum system, the laser level can self leveling. If the tilt angle of laser tool is ≤ 4°, the beam will flash to indicate the unlevel condition. LOCK "PENDULUM" + PRESS "POWER" Under Manual Mode, the laser tool locks the cross-line for use at any angle. The level tool will blink every 3-5 seconds to remind you that it's manual mode now. UNLOCK "PENDULUM" + LONG PRESS "POWER" When in Pulse Mode, HUADER laser level line tool can be used with a laser detector for working in even brighter environments or at greater working distances. Read the Safety Instructions and Manual thoroughly before using HUADER laser level. Do not stare directly into the green beam or view directly with optical instruments or set up the laser at eye level.Do not disassemble the laser tool. There are no user serviceable parts inside.Do not modify the line laser in any way. Modifying the line laser level may result in hazardous Laser Radiation Exposure.Do not operate the level around children or allow children to operate the laser.