No more fumbling with stoppers to keep your storm door open. Simply push the door open slowly until you hear a click and the door remains open at a 55 degree angle. To close the door simply push the door open further and release. This closer replaces door closers with a torsion bar. If the door closer you are replacing does not have a torsion bar you will need to drill new holes. This closer will keep the door open in only one postion. A hold open washer can be used to keep it open in variable positions. This is a pneumatic (air pressure) door closer for storm doors that are 1-1/2" to 2-1/4" thick. A storm door chain is recommended to protect the closer and door from gusts of wind. The tube is made of aluminum.