Most of the locks sliding glass doors I come across are an absolute joke and should never be protecting you, your family, and your home from criminals and crazy people. The hardware is made of crappy plastic and the lock cylinder can be picked with a Bobby pin or a paperclip. The latches are never aligned and half the time they can be unlocked just by wiggling the door up and down! There's a great solution for this, and it's a friggin broomstick cut to the right size. They do make a product for this called a security bar but I think the old fashioned dowel or broomstick is the better option. Only because I has 2 different resting position you can use when it's not engaged. The first is in the down position - the problem with this is if someone is wiggling the door a lot or maybe banging on it, it could possibly vibrate Loose and fall down. Leaving the door completely unlocked. The other is the up position - the problem with this is that if you slam the door hard behind you when you walk out the door and the vibration makes the bar fall down, thus locking the door so securely that even I could not get through it without breaking the glass. And what if all if your other doors are locked too? Oh yeah, you call Ben the locksmith!