DIMENSIONS: For pets up to 100 lb; flap opening size is 10.2" W x 17" H; measure your pet to ensure comfortable use. U.S.-BASED CUSTOMER CARE: Our pet product experts are here to help you and your pet and are available by phone, email or chat if you have any questions. STORM DOOR/WINDOW/PORCH COMPATIBLE: Works with most metal or vinyl coated fiber screens. SAFE AND SECURE: Large door has sliding wind-locks that are strong enough to resist flapping open in the breeze but not so secure that your dog can’t run through; small door locks to prevent entry. DURABLE DESIGN: High-impact plastic frame surrounds a strong mesh that is puncture and tear-resistant for long-lasting use; large door is reinforced with fastening screws QUICK, DIY INSTALL: Snaps directly into your existing screen door, window or porch screen for easy installation, and blends perfectly with your existing screen. ENCOURAGE EXERCISE AND INDEPENDENCE: Give your cats and dogs freedom to go in or out without asking for your help to open the door—perfect for potty breaks or play time.