{"product_id":"southwark-metal-73c151418-rectangular-to-round-transition-14-inches-x-20-inches-x-18-inches","title":"Southwark Metal 73C151418 Rectangular to Round Transition 14 Inches X 20 Inches X 18 Inches","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\u003cp\u003eThe Southwark Metal 73C151418 is a rectangular to round transition fitting designed for HVAC duct systems. It connects rectangular ductwork to round collar openings, making it a key component in air distribution installations. HVAC technicians, sheet metal contractors, and mechanical contractors rely on this type of fitting when transitioning from rectangular trunk lines or plenums to round branch ducts. This fitting measures 14 inches by 20 inches on the rectangular opening and 18 inches in diameter on the round collar. The overall height of the unit is 12 inches, providing a gradual taper that supports smooth airflow through the transition. The round collar height on 18-inch diameter fittings is approximately 3 inches, giving installers enough length to seat and secure the round duct connection properly. Constructed from hot dipped galvanized steel that meets ASTM A653 CS Type B standards, this fitting delivers reliable corrosion resistance in both supply and return air applications. The 28-gauge steel construction provides the structural rigidity needed for commercial and residential duct systems without adding unnecessary weight. The galvanized coating protects the fitting from rust and degradation, extending service life even in humid or high-moisture environments. This fitting is manufactured in the USA, which is important for projects with domestic sourcing requirements. It carries a Prop 65 designation, so appropriate handling precautions should be observed. The 73C product family from Southwark Metal covers a wide range of rectangular to round transitions, available in sizes from 6 inches by 6 inches through 20 inches by 20 inches, with other sizes available upon request. Whether used in new construction, HVAC retrofit, or duct replacement work, this transition fitting provides a secure and airtight connection between duct shapes.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eRectangular to round transition fitting sized 14 inches x 20 inches rectangular opening to 18 inches round collar\u003c\/li\u003e\n\u003cli\u003eMade from 28-gauge hot dipped galvanized steel per ASTM A653 CS Type B for corrosion resistance and durability\u003c\/li\u003e\n\u003cli\u003eManufactured in the USA with an approximate 3-inch collar height on the 18-inch diameter round end\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eProduct Highlights\u003c\/h4\u003e\u003cp\u003eThe Southwark Metal 73C151418 rectangular to round transition is a durable, galvanized steel duct fitting built to connect 14 inches by 20 inches rectangular ductwork to an 18-inch round collar. It meets ASTM A653 CS Type B standards and is manufactured in the USA for reliable use in residential and commercial HVAC systems.\u003c\/p\u003e\u003ch3\u003eProduct Information\u003c\/h3\u003e\u003ch4\u003eStandard Information\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand\u003c\/strong\u003e: SOUTHWARK METAL\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number\u003c\/strong\u003e: 73C151418\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial\u003c\/strong\u003e: Galvanized Steel\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGauge\u003c\/strong\u003e: 28 GA\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDuct Size\u003c\/strong\u003e: 14 inches x 20 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCollar Diameter\u003c\/strong\u003e: 18 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHeight\u003c\/strong\u003e: 12 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLength\u003c\/strong\u003e: 14 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWidth\u003c\/strong\u003e: 20 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight\u003c\/strong\u003e: 3.974 pounds\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGalvanized Coating\u003c\/strong\u003e: Yes\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCountry of Origin\u003c\/strong\u003e: USA\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUnit of Measure\u003c\/strong\u003e: EA\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"SOUTHWARK METAL","offers":[{"title":"Default Title","offer_id":51121076764978,"sku":"73C151418","price":39.22,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/304885231.webp?v=1777747721","url":"https:\/\/voomisupply.com\/products\/southwark-metal-73c151418-rectangular-to-round-transition-14-inches-x-20-inches-x-18-inches","provider":"Voomi Supply","version":"1.0","type":"link"}