Pet doors are a great idea, but pets come in all shapes and sizes.
This means that you need to consider how tall and how wide your pet measures. Not forgetting if you have more than one pet, both needs to be considered, especially if they are considerably different in size.
You wouldn’t want your small pet having trouble climbing over the step over, or your large pet having to crouch down and squeeze in through the pet Door.
The infographic below by Endura Flap is an easy way to help pet owners gain a rough idea how big the pet flap would be depending on the bread/animal.