This pet door fits a hollow or solid door. It has a flexible PVC flap with magnetic energy seal. Accommodates door widths from .88 to 2.25 inch. Opening size 8  x 12 H inch. For pets up to 40 lbs., including the Beagle, Cocker Spaniel, Dachshund, Scottish Terrier and King Charles Spaniel. Recommended for indoor applications or outdoor access to covered areas, as well as outdoor applications for temperate climates. For low to medium usage. (Select a metal door for frequent usage)