Review on 🔒 Enhance Home Safety with Defender Security U 9819 Sliding Window Security Lock - Economy Aluminum, Pack of 4 (Silver) by Christopher Yap

What is not visible in their photo, but in mine, is that the product has the wrong type of screw. Usually these locks have flat screws (second photo) that press against the window frame. They came with very sharp, pointy points. They are so sharp that if I keep tightening them they could pierce the window frame (I could see them start to dent and stop). In addition, the contact area with the frame is so small that they do not prevent the window from opening. I think if you are really dedicated and pierce a window frame with it, it will hold.