It comes in many varieties and options like you can buy one with interchangeable glass panels and window screen panels. A storm door with a doggie door is an ultimate solution that allows the dogs to get in and out conveniently.
Puppies are just like young humans they are often negotiating going upstairs or downstairs but cannot manage to come back safely. Sometimes it led to injury especially in case of when stairs are made of concrete or iron. Older dogs also share the same rick they can fall off from the stairs because they lack energy and their in-firmness can lead to an accident.
The best dog gate with cat door acts as a temporary barrier for the dogs, won’t allow them to visit the other side (the sectioned off area) while the built-in small door permits the small animal like cats to pass through, easy to operate and allow locking both of doors to restrict access of all animals.