This pneumatic door closer uses air pressure to provide sure, silent closing. It is designed for light to medium-weight doors up to 1-1/4” thick, 30 to 50 lbs. The door closing speed is adjustable, ensuring that doors shut securely every time. Seasonal adjustment options allow you to swap between window and screen on your door. It includes all necessary brackets and screws for installation and is easy to install using the existing holes on your door (if this was the model on the door previously). The included storm door chain prevents door from taking off in heavy winds.