Speedi-Boot SBH-161614 SRA 16-Inch Width by 16-Inch Length to 14-Inch Diameter Square-to-Round Register Vent Boot with Adjustable Hangers Adjustable telescoping hanger arms that can be shortened as well Foam gasket seals air tight at installation to back of sheetrock Dust and debris cover preventsconstruction contamination Mud ring prevents gaps between the boot and sheetrock Dust and debris cover provides a plug for HVAC pressure testing