FLYZZZ Adjustable Sliding Window Screen, 2 Ways Aluminum Frame Expandable Window Screen (15.74 ''h x21-40''w) or Convert to Vertical (21.65" h x 15-28" w), B

If you have windows without a screen installed or a track to install screens, this is a viable option depending on the location of the window. Especially if they are wooden windows (where magnetic screens won't work). They are held in place by the window itself. Raise the window, insert the screens, lower the window to hold the screens in place. I wouldn't use these on higher floor levels without a balcony under the window as they could fall while you're raising or lowering the window, but for home or small office use for some air flow minus bugs (although, depending in your windows, there may not be a continuous "seal"...my windows are old & wood and there is a small gap), these are a good, quick & inexpensive option or temporary fix until a permanent screen can be replaced. They don't take up much room when not in use. They slide open to the width you need. They don't roll like butta, but they work! If you want butta-smooth sliding, you're probably going to pay a lot more, if there are any this type of that quality. Can't speak to how we'll they keep water out as I use them in an area that's under cover, but you probably won't have your windows open in a downpour anyway. Am considering purchasing another single screen for a 3rd window. But I would suggest buying in sets if you don't need a single screen.... more bang for your buck.

This item perfectly solved an unusual problem. I have 2 screen doors that are retractable onto a roller along the side, are not separate doors. Love them! They can't be anchored to a stationary frame, so the bottom edge can be pushed out. Then I got a cat who is a Houdini and she soon figured out she could push the bottom edge out far enough to escape. Amazon usually has a solution and this is it. I can spread these expandable screens across the bottom of the roller screen and H. can't get out but can see the outdoors. If I used the expandable screen alone, she could easily jump over it. We are all happy here! Thank you!

Work as expected. I ordered for 2 different size windows. A little tight on the smaller one but works perfect on bigger on. Nice to get a breeze without the bugs.

These new construction rental properties come with a high price tag but, NO screens for the windows??!! Couldn't open my windows without letting everything from outside in. I was tired of not getting any fresh air. Looking for a solution and found it. These adjustable screens work perfectly. No assembly just pop it in the window and Go!

Just needed something to help keep the critters out when I wanted my window open at night. Perfect solution. East to store when not in use.

Does what it is supposed to. Inexpensive but not super flimsy. Good enough to keep my cats from trying to jump out of the window

The screen has a strange rainbow effect as if you are looking through an oily substance. However, the business owner was super helpful and worked to fix the issue.

Out of the box and onto the window frame, 10 second installation! Sealed in great, no gnats, ants or flies get in. Definitely for windows that raise vertically. And it's for newer modern windows, not the old heavy wood types.