DUCT BOARD FIBERGLASS DUCTBOARD TRANSITION BOXES PLENUM BOXES UL APPROVED FLEX DUCT 25 FEET PER BAG R6 INSULATED FLEX DUCT MOBILE HOME FLEX DUCT UL APPROVED COLLARS TAB STARTER COLLARS SCOOP/DAMPER COLLARS FLEX COUPLERS REGISTER BOXES R6 INSULATED FLANGED REGISTER BOX UL APPROVED