This heavy duty pneumatic (air pressure) door closer is appropriate for use on heavier aluminum, steel or wood storm and screen doors from 1-1/4� to 2� thick. This series is for out-swinging storm doors. The door closing speed is adjustable with the air adjusent screw at the end of the closer tube. The closer tube is made of aluminum which will not rust. The closer can be installed at the top, middle or bottom of your door, depending on the construction of 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).