{"product_id":"air-flow-products-77f182020-transition-boot-flange-18x20","title":"Air Flow Products 77F182020 Transition Boot Flange 18x20","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\n\u003cp\u003eThe AIR FLOW PRODUCTS 77F182020 is a straight transition boot with flange, designed to connect square or rectangular duct openings to round collars in forced-air HVAC systems. The 77F series boot transitions an 18x20 inch rectangular opening down to a 20-inch round collar, making it a practical fitting for supply or return air trunk-to-branch connections. This type of fitting is installed by licensed HVAC technicians and sheet metal mechanics during new construction, system retrofits, and ductwork modifications where a square-to-round transition is required.\u003c\/p\u003e\n\u003cp\u003eThis transition boot is suited for residential and light commercial forced-air applications where trunk lines must step down to branch runs or collar tie-ins. The flanged design simplifies connection to plenums, air handlers, or rectangular duct sections, and the straight profile keeps the fitting compact in tight ceiling or floor cavity installations. Installers working on supply-side distribution systems will find the 18x20 inlet and 20-inch collar dimensions appropriate for medium-to-large air handler configurations.\u003c\/p\u003e\n\u003ch4\u003eKey Features\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003eSquare-to-round geometry transitions an 18x20 inch rectangular duct opening to a 20-inch round collar\u003c\/li\u003e\n  \u003cli\u003eIntegrated flange provides a secure mounting surface for connection to plenums or rectangular duct sections\u003c\/li\u003e\n  \u003cli\u003eStraight profile minimizes depth requirements in confined ceiling, floor, or wall cavities\u003c\/li\u003e\n  \u003cli\u003e77F series design engineered for consistent fitment in forced-air duct systems\u003c\/li\u003e\n  \u003cli\u003eSuitable for supply and return air applications in residential and light commercial systems\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eCompatibility\u003c\/h4\u003e\n\u003cp\u003eDesigned as an OEM-style sheet metal transition fitting for use in standard forced-air HVAC ductwork systems requiring a square-to-round transition at an 18x20 inch rectangular opening with a 20-inch round collar outlet.\u003c\/p\u003e\n\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\n\u003cp\u003eInstallation should be performed by a qualified HVAC technician or licensed sheet metal mechanic in accordance with applicable mechanical codes. Power down and lock out the air handling unit before beginning any ductwork modification. Seal all joints with listed duct sealant or approved foil tape per SMACNA guidelines to prevent air leakage. Support the fitting per local mechanical code requirements to avoid stress on adjacent duct connections.\u003c\/p\u003e\n\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eInlet Size\u003c\/strong\u003e: 18x20 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCollar Diameter\u003c\/strong\u003e: 20 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTransition Type\u003c\/strong\u003e: Square to Round\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eProfile\u003c\/strong\u003e: Straight\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFlange\u003c\/strong\u003e: Yes\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSeries\u003c\/strong\u003e: 77F\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eStandard Information\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBrand\u003c\/strong\u003e: AIR FLOW PRODUCTS\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number\u003c\/strong\u003e: 77F182020\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"AIR FLOW PRODUCTS","offers":[{"title":"Default Title","offer_id":51343473705266,"sku":"77F182020","price":102.76,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/310552914.jpg?v=1782021857","url":"https:\/\/voomisupply.com\/products\/air-flow-products-77f182020-transition-boot-flange-18x20","provider":"Voomi Supply","version":"1.0","type":"link"}