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. The door closer's cylinder measures 1.5� in diameter and it has an overall length of 13�. 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. The Touch-N-Hold function allows you to keep the door open by pressing a button, the mechanism disengages once the door is pushed.