I remember the first pet door I purchased some years ago, not much to chose from and all cheap plastic. Before the day was over my large dog (Boxer ) poked her head through the opening and was wearing it for a collar. Many years later my Daughter bought a new house and wanted a pet door for the cat to reach the cat box in the basement. I bought one at Menards and nothing much had changed , expensive, not much to chose from and all cheap plastic. After much frustration with the telescoping piece that I knew wouldn't last and the general ugly appearance, I told her I could make one much better and nicer looking. She was so pleased she said you should start making these! I've since found many others were as disappointed as I was on what was available out there. I started with the one design and have since added quite a few models including exterior dog doors.