Wall Entry Aluminum Pet Door Small Model: PPA11-10915 Fits walls 4 3/4" to 7-1/4" thick Dimensions - 9-3/4" x 13-1/2" Flap Opening Dimensions - 5" x 7" Great for pets up to 12lbs

Wall Entry Aluminum Pet Door Medium Model: PPA11-10916 Fits walls 4-3/4" to 7-1/4" thick Dimensions - 12-3/4" x 17-1/2" Flap Opening Dimensions - 8" x 11" Great for pets up to 40lbs

Wall Entry Aluminum Pet Door Large Model: PPA11-10917 Fits walls 4-3/4" to 7-1/4" thick Dimensions - 14 3/4" x 21-1/2" Flap Opening Dimensions - 10" x 15" Great for pets up to 100lbs