Review on Enhanced Vinyl Sliding Window Locks by Defender Security - Effortless Installation for Securing Windows - Durable White Diecast Construction (Pack of 2) by Dale Hing

As mentioned, the "cam-lock" function does not exist due to poor workmanship. This means the lock will not "spin" when you turn the lever after tightening. In fact, he loosened it up a bit by flipping the lever on all 4 locks I received. That being said I was only able to screw it in enough by hand and it holds the window securely. Great design? Yes. Bad performance? Absolutely safe. I can do as someone else mentioned and sharpen the lever cam to actually work, but that seems like a lot of work for a cheap little window lock. Important Note: They will not work on steel framed windows. . Teeth need vinyl (softer than steel) to properly bite. This is probably why the listing says they are made specifically for vinyl windows. But apparently some people didn't read this before buying and left 1 star reviews.