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

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)!

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 💯

I live in an apartment and can't drill the window frames without losing my deposit. The Defender U 9809 got my attention because it does not require drilling, screws or anchors to install. If you install with care, they will not damage the finish of your windows or frames. If your windows are white the locks will match perfectly. They allow me to have a window air conditioner that requires the window to be raised and locked.Security? You'll risk breaking vinyl window frames if you tighten the locks sufficiently so they are impossible to budge. That said, with two of these in place I think you'd need a pry bar to open the window from the outside. It would be easier to break the window or go elsewhere. I have peace of mind and am comfortable accepting the Defender solution. If you need absolute security, consider getting vertical rods like these: https://www.amazon.com/Window-Security-Locks-Onto-Frame/dp/B00PG1EP86/

I was skeptical when I first received them but they are easy to install and definitely effective. I installed these on windows that would slide up to open. I would recommend installing them snugly above the window that slides up and not leave a gap.

Great item

As others have noted, the "cam lock" function doesn't exist, due to shoddy manufacturing quality. What that means is the lock doesn't "crank down" when you flip the lever after tightening. In fact, flipping the lever actually loosened it somewhat on all of the 4 locks I received.That being said, I was able to simply screw it tight enough by hand and it holds the window securely.Great design? Yes.Poor execution? Most definitely.I may do as someone else mentioned and file down the cam of the lever so it actually works, but that seems like too much work for a cheap little window lock.Important note: These won't work on steel-frame windows. The teeth need vinyl (softer than steel) for proper grip. That's probably why the listing says they're specifically for vinyl windows... But apparently some people didn't read that before buying then left 1-star reviews.

My rental house has new Anderson double horizontal siding windows. I don't have central air, so I wanted to be able to leave some windows open while I am gone working during the day so it's not an oven when I return. Also I just installed a portable AC unit in the bedroom.These work exactly as advertised and are very simple. I would point out two things:1) you need two per window if you are using them to secure partially open windows. With just one, you can knock it off by closing the window a bit and then ramming it against the lock. Reviewers with vertical sliding windows put one on each side but for the horizontal windows you'll want to put two next to each other. Other reviewers mentioned using 3m sticky shelf liners to prevent a single one from being defeated, but I haven't tried that.2) if you have dual sliding windows, these will only lock the inner window. If the normal locking mechanism is the type that binds one window to the other in the center, then these are not a complete security solution, as the outer window can still slide freely. I added the outer window stick-on devices that you can popout-to-lock / fold-in-to-slide to complete the solution.

Love these! I had different ones from Home Depot that only fit a certain size of window. These fit everything. They're easy to use and attractive. As well as securing the window from a break in while allowing it to be open for fresh air.