6\ HVAC Duct Manual Volume Damper with Sleeve - Galvanized Sheet Metal Round Volume Damper Airflow Ducting Branch, Adjustment Handle HVAC Air Balancing System - Easy to Install
- 26 Gauge Galvanized Steel, Single Wall with No Insulation.
- Built with standard plaster ground flange all the way around the square portion..
- Connects a 10" Round Duct to a 10" x 10" Diffuser or Register Vent..
- The ceiling box is nailed into the attic rafters and plastered or dry walled around the flange called plaster ground..