6 Sliding Window Locks Window Stopper/Stop Security Locks with Keys, Donuts Adjustable Aluminum Alloy Window Safety Lock for Home and Office

The keys are so long that with blinds in the window, I couldn't even use them, I had to go buy an Allen wrenches in the correct side just to install them. Also, the back part is one thickness which means if your windows are loose at all, they can slide behind the lock and still be opened. The back needs to have a jutting piece to keep this from happening, or else the back portion needs to be thicker than the rest by at least twice. They looked really heavy duty, and they are, but they aren't at all right for those crappy apartment windows we all need them for.

Really easy to pop off with a medium amount of force on the window.