I contacted American Sliding Door to install pet doors in my sliding glass door and in the screen door for the slider. I was so happy to have a local provider (I like to support the local businesses if possible). I knew I was going to have to replace the glass on the sliding door in order to have the pet door through the glass. I found the price very reasonable considering the glass replacement, screen door, and pet door hardware. They are excellent quality pet doors. The pet door in the slider comes with two flaps, one inside and outside the glass, this keeps the door insulated. There are also magnets that hold the pet door closed from wind or airflow. If you need to remove any of the magnets or flaps to help during the training of your pet, it is fairly easy with this pet door. Despite already having a screen door, the entire screen door needed to be replaced to accommodate the pet door hardware in the screen. I find the quality of the new screen door much better than the original so I found the additional cost in the screen door to be worth it. The workers were extremely professional. They offered to install the door shortly after everything arrived in their shop. Everything came out perfect. They took there time to make sure we were going to be happy with the end product.