All our Window Covers are heavy duty, waterproof, non-scratching, poly-fabric with felt backing..... They keep warmth in your home and cold drafts out. ..... Covers are sewn using reinforced nylon thread for non-tearing and long-lasting seams and corners and are reusable year after year. .....Our Covers have a bottom and can be used for horizontal and vertical applications. ..... Heavy-duty security strapping (400lbs break strength) and new steel buckles are included for a very secure and positive attachment for both outside and inside..... Your cover cannot be taken off easily or will be blown away! ......Can this cover be used if you have brackets supporting the a/c unit outside? YES! The cover can be slid between the top of the bracket and the bottom of the a/c unit by just removing a screw temporarily and sliding the cover material under the unit, poking a hole , and then replacing the screw.....We offer a full 2 year manufacturer"s warranty ..... To request a custom size go to BUYER MESSAGES and send the size or sizes you want when you place your order.....Proudly made by a Vietnam Vet. in America.