I live in the foothills of the Rocky Mountains. Rarified air and all that stuff. That means that UV does a number on anything it reaches. Outdoor furniture degrades quicker than you would ever imagine. So, window screens, being on the outside of our UV-filtering windows, get hammered. So far (5 years) the screen itself hasn't degraded, but every black pull tab on our screens has turned hard and then cracked when you try to use it. I tried the hack of using duck tape, but that only resulted in UV damaged duck tape sticking to the screen frames (that took about one season, I think). I was resigning myself to having to change out the tabs every other year, and then found these. They are about twice as wide as the black pull tabs my screens came with. Not a big deal, as they are also metallic, so don't show as much as the black. Putting them in and out was tricky, but not because of the product. On one screen, the spline had disintegrated under the UV, and so tore every time I tried to pull it out. On almost all of them, the screen material was adhering to the frame. You have to lift the screen material fully out of the track to place the tab under it, so that was a little dicey, trying to avoid tearing the screen. But those are UV problems, not this product's problems. They come in a pack of 25. Why? Dunno. All my windows use 2 pulls each... However, 25 wasn't enough to do all my windows, so I'll be buying another pack to finish the rest. That'll give me an even number, lol! I can't imagine that UV will be able to damage this metal. My only quasi-concern is that they might get hot in the direct sun, so I'll have to be careful if I try to take them out on a sunny day. That's probably not going to be an issue, though. UV can s u c k it. Tools needed: small slotted screwdriver for prying out the spline and the old tabs, a screen mouse (or similar) for replacing the spline once you have the new tab in place, scissors to cut the spline, as even if you reuse the old spline, it will stretch when you replace it, and replacement spline (on hand just in case the old breaks. If you don't know the size of spline you need, cut a sample off one of your windows before you go to the store; the size differences are very subtle, and you can't tell just by looking. You have to compare to what you have.).