Inner telescoping frame that adapts to doors of 1/2" to 1 3/4" thickness High quality aluminum construction Clear flap allows pet to see if slide is in place Tamper Proof Mounting System, door can't be removed from outside Spring loaded Lockout Slide Pet Size: Medium 13 to 35 lbs Pet Door Cut Out: 7 1/2" x 13 3/4" Pet Door Flap: 7" x 11 1/4" WARNING: This product can expose you to chemicals, which are known to the State of California to cause cancer, birth defects or other reproductive harm. For more information, visit www.P65Warnings.ca.gov Perfect Pet Door Mount Deluxe in White, Size: Medium | PetSmart