Damper sleeves are used to regulate the amount of air flowing through each branch of your heating and air conditioning system. They should be located in areas that are accessible for adjustment. Typical uses are for rooms that get minimal use and can be closed of for extended periods of time or rooms that need different amounts of air flow in the summer and winter. Damper Sleeves are made from Galvanized Steel and have a 1 ½” Stand-Off for the locking Damper Handle to raise it above any fiberglass insulation you may wrap around the outside of the damper sleeve after installation.