This works on 2 mounting screws, and secures to itself with another. Even with a lightweight monitor, you MUST install into studs (not always convenient), and make sure you get your security screws right the first time - they will strip themselves out...

Don't carry this product anymore. I got so frustrated that I may not buy anything online from NewEgg again in fear I will get another bad product and have to PAY to return ship it....horribly experience...if you have gotten any other reviews like this...