Refer to packaging for complete easy to install instructions.
PetSafe Extreme Weather Door - Large
Dimensions: Opening: 10.13"W X 15.75"H
Pet Size: For Dogs up to 100 lbs.
PetSafe Extreme Weather Door - Medium
Dimensions: Opening: 8.13"W X 11.75"H
Pet Size: For Dogs up to 40 lbs.
PetSafe Extreme Weather Door - Small
Dimensions: Opening: 5.13"W X 7.63"H
Pet Size: For Dogs up to 15 lbs.