Features: LARGE CAT DOOR FOR BEEFIER BREEDS: Own a bigger kitty like a Maine Coon, Burmese, Egyptian Mau This cat door fits most cats MOST SECURE CAT PORTAL YOU CAN FIND: Most pet doors for cats fasten with flimsy tape But this kitty door attaches firmly with sturdy screws Installs in minutes stays snugly in place KEEPS BIGGER DOGS AT BAY: This large cat door stops your big-breed dog from getting into the cat food and kitty litter NO ANNOYING FLAP: Ever try training a cat to use a flap-covered pet door It's an exercise in frustration Fortunately, our cat door is 100 percent flap-free, so your pudgy feline can walk right through FITS SOLID and HOLLOW DOORS: Unlike most big cat doors, our cat door fits interior doors Unique design keeps cat's paws from getting stuck inside hollow-core doors Specification:Material: ABS PlasticFrame size: height 22 5cm width 27cm thickness 5 5cmInner frame size: inner diameter 17 5cm inner groove thickness 3 5cmPackage Included:1 Set Cat Door (with screws and screws cap)Warm Tip: Because the thickness of each door is different, if there is a problem of inappropriate screws during installation, you need to buy them separately It can be directly glued on the glass with glass glue