18x22 inches - outside - 13 1/4 x 19 1/8 - Inside - PetSafe SmartDoor Connected Pet Door for Cats and Dogs Installation Adaptor, Large, ZAC19-17246 SmartDoor Installation Adapter Large
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18x22 inches - outside - 13 1/4 x 19 1/8 - Inside - PetSafe SmartDoor Connected Pet Door for Cats and Dogs Installation Adaptor, Large, ZAC19-17246 SmartDoor Installation Adapter Large