DINGCHAO Self Leveling Red Beam Cross Line Laser Level for Construction,Horizontal Vertical Line Laser Leveling Tools,with 360 Degree Pivoting Base,Aluminum Hard Case,Protective Glasses SELF LEVELING SYSTEM : Pendulum locks when turned off; Pendulum unlocked to activate laser beam, it auto-levels when placed within 4 degrees of horizontal/vertical line TILT FUNCTION: Press OUTDOOR key about 3 seconds,laser beams would not flickering when tilting any angles RECEIVER FUNCTION: Press OUTDOOR key 1 second,then you can work it with a receiver 360 DEGREE ROTARY:with a 360 degree rotary base, easily to rotate laser level manually MICRO-ADJUSTMENT: adjusting the rotary knob to rotate laser level in 0.1 degree