I bought this to replace a screen in my horse trailers. I’ve heard horror stories of things blowing through the windows going down the road and injuring horses. A cigarette even made it in one trailer and started a fire. So I don’t want the windows open without screens. This screen has brackets with screws that you mount in the corners and then use the Velcro loops on corner of screen to hook on. You should order a screen that is larger than your opening. This way the sides (that don’t have velcro) will be tight around the opening and not gap or let things come through.