This large cat door is specially designed for cats weighing up to 25 pounds. Transparent unbreakable LEXAN flap 7.5 x 10.5 flap with 4-way lock. For cats 2 - 25 lbs. Flap size 7.5 x 10.5 Cutout size 8.25 x 13.75 Door thickness range 1.25 - 1.75 Interior or exterior use