1. Adopting a wavelength of 635nm semiconductor laser. The laser line is clear and bright. 2. Self leveling and beyond the scope of automatic alarm function. 3. Emit four vertical lines and horizontal lines, plumb below point. 4. Design of the chassis circular bearing can rotate 360 degrees to instrument, make a beam of light to any areas of need. 5. Fine adjustment knob configuration can be fast and accurate to find the target.