Sunydeal Articulating Flat Panel TV Wall Mount for Vizio E470-A0 E500i-A0 M501d-A2R E500I-A1 E550i-A0E E601i-A3 LF501EM4F LF501EM4 LF551EM5 E601I-A3E TV Security screws on both arms lock the screen in position for additional security Rigorously stress tested to ensure security, safety and peace of mind level meter, help to adjust the horizontal Our screws might not be long enough for some TV models, Please check the PARTS image aboved and your TV's VESA before order. Make sure the wall installed TV bracket is firmness and tightness, such as concrete wall, solid wood wall, do not install in hollow and floppy walls.