Prime-Line U 9809 Sliding Window Lock for Vinyl Windows – Easy Installation to Keep Windows Securely Closed – Diecast Construction, White (2 Pack)

I put these on the bedroom windows in my kids' rooms. I put 2 on each window (1 on each side). I leave about 3 inches so air can flow, but no one can get in. Better than putting bars on windows since bars cannot be removed in case of emergency/fire. I feel so much safer going to sleep and knowing my kids will be there in the morning and no one can get in. I have purchased several more at this point.Here is some helpful info:I use them on double-hung windows myself. So, if you look at the picture of the little lock, you can see a square on top, a turning knob up front, and tucked behind is a piece that moves forward and backward. You take the lock and open that sliding portion by turning the knob. You open it up big enough to slide the "teeth" of the lock onto the window frame. (See pics) This can attach to any frame as long as the frame is thin enough to fit in the teeth. The teeth open about 1/2", so if the frame you want to attach to is 1/2" thick or thinner/smaller, then you are good to go. Slide it onto the frame (see pic) and turn knob to tighten. Once you have it good and tight, you push the knob flat and that will secure it even more.Note - make sure to use BOTH locks on a single window. In testing, I placed one lock in a way that it would allow the window to open 3-5 inches. I then "pretended" I was trying to get in and took the window from the bottom and shoved it up pretty hard. I did this a few times, and there is enough wiggle by going up and down with the window that I can slowly, but loudly, get the lock to inch up until there is enough room for me to climb into the window. However, it is really hard to do that when BOTH locks are used on either side of the window. Having two in place is a pretty secure situation.I also like that I don't have to screw these into anything, which not only damages the window frame but also allows for only one position. These allow you to move them up and down at anytime, or just remove them. Meaning, you can place them in a way to allow the window to open 3" or 4" or almost all the way open, or almost all the way closed, wherever you want, and you can change it from day to day if you like. Nothing permanent.I love these!Sorry about some of the pics. Amazon would not allow me to flip a couple of them. Hope it still helps.

The media could not be loaded. These window locks have definitely earned my anxiety’s seal of approval! They work incredibly well and bring me that extra bit of security I was looking for. Ignore the scratches in my pictures—one of them fell off, and my dog (she decided it was her new chew toy) went to town on it. Thankfully, they’ve held up great despite the “extra testing.”They’re super easy to twist on and off, making it simple to open and close the windows. The only slight annoyance? You do have to twist them all the way to adjust the window, which makes sense for security, but can be a bit of a pain when you just want a quick crack of fresh air after overcooking something!One bonus I appreciate is that they’re just tricky enough to keep my child puzzled, which adds that extra layer of peace of mind. I’ve got these on all our windows, and I’d highly recommend them to anyone needing a little extra home security (or pet durability)!

First off, remove and throw away the star-shaped steel washer. It will destroy the zinc clamp after only a few uses. (Steel is much harder than zinc). Replace it with a softer washer like plastic.Whether the lock works is entirely dependent on the shape of the vinyl window where you clamp the lock. Unless the vinyl is straight up and down on the inside and outside, the lock won't clamp securely, (not even if you crank the lock down so tight that it breaks). Then opening the window will simply knock the lock off or slide it out of the way.I tried the lock on the windows at various places, and the shape of the vinyl is key.But to reiterate, when it works, it works great.

Better than putting bars on windows since bars cannot be removed in case of emergency/fire. I feel so much safer going to sleep and knowing my kids will be there in the morning and no one can get in. I have purchased several more at this point.Here is some helpful info:I use them on double-hung windows myself. So, if you look at the picture of the little lock, you can see a square on top, a turning knob up front, and tucked behind is a piece that moves forward and backward. You take the lock and open that sliding portion by turning the knob. You open it up big enough to slide the "teeth" of the lock onto the window frame. (See pics) This can attach to any frame as long as the frame is thin enough to fit in the teeth. The teeth open about 1/2", so if the frame you want to attach to is 1/2" thick or thinner/smaller, then you are good to go. Slide it onto the frame (see pic) and turn knob to tighten. Once you have it good and tight, you push the knob flat and that will secure it even more.Note - make sure to use BOTH locks on a single window. In testing, I placed one lock in a way that it would allow the window to open 3-5 inches. I then "pretended" I was trying to get in and took the window from the bottom and shoved it up pretty hard. I did this a few times, and there is enough wiggle by going up and down with the window that I can slowly, but loudly, get the lock to inch up until there is enough room for me to climb into the window. However, it is really hard to do that when BOTH locks are used on either side of the window. Having two in place is a pretty secure situation.I also like that I don't have to screw these into anything, which not only damages the window frame but also allows for only one position. These allow you to move them up and down at anytime, or just remove them. Meaning, you can place them in a way to allow the window to open 3" or 4" or almost all the way open, or almost all the way closed, wherever you want, and you can change it from day to day if you like. Nothing permanent.I love these!

Is perfect and works great also good quality 👌. I did buy from different places it worked ok but in a month it didn't tide good anymore but this one i could tell will last for long. Thx for perfect discrepancies. I'll buy it again for windows too.I recommend it 💯