This is a 2-Piece Flap that fits Several Pet doors: The Johnson Ultimate Dog/Pet door The PetSafe Ultimate Pet/Dog Door The PetSafe Economy Pet Door

InnerFlap measures 13 x 18 1/2" Inner Flap with Outer Ring measures: color: 16 1/2 x 20 3/4" Material is flexible and dark-tinted Known as a small size or by part# X-VA-11