{"product_id":"national-mfg-n350-819-4-inch-ss-spring-door-hinge-ul-fire-door","title":"National Mfg N350-819 4 Inch Ss Spring Door Hinge Ul Fire Door","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\u003cp\u003eThe NATIONAL MFG\/SPECTRUM BRANDS HHI N350-819 is a 4-inch stainless steel spring door hinge designed for self-closing door applications. Manufactured from cold rolled steel with a stainless steel finish, it features independently adjustable closing speed and adjustable spring tension, giving installers precise control over door operation after mounting. The square corner design fits standard hinge cutouts without modification. This hinge carries UL approval for use on fire-rated doors, making it a code-compliant choice for commercial and residential applications where fire door hardware is required. Each package contains 2 hinges.\u003c\/p\u003e\u003cp\u003eThis hinge suits standard interior and fire-rated door installations in residential, light commercial, and multi-family settings. It is commonly specified where building codes or fire safety requirements mandate self-closing hardware on corridor, stairwell, or utility room doors. The adjustable tension and closing speed make it adaptable across a range of door weights and swing frequencies common in these environments. Licensed contractors, carpenters, and door hardware specialists install this type of hardware as part of fire door assembly work.\u003c\/p\u003e\u003ch4\u003eKey Features\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003eUL approved for fire-rated door assemblies\u003c\/li\u003e\n\u003cli\u003eAdjustable closing speed for controlled, consistent door operation\u003c\/li\u003e\n\u003cli\u003eAdjustable spring tension to accommodate varying door weights\u003c\/li\u003e\n\u003cli\u003eFits standard hinge cutout — no mortise modification required\u003c\/li\u003e\n\u003cli\u003eSquare corners for clean fit on standard door and frame preps\u003c\/li\u003e\n\u003cli\u003eCold rolled steel construction with stainless steel finish\u003c\/li\u003e\n\u003cli\u003eSold as a package of 2 hinges\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eCompatibility\u003c\/h4\u003e\u003cp\u003eDesigned as an OEM-style replacement or new-installation spring hinge for standard door preparations requiring a 4-inch self-closing hinge on fire-rated or non-rated door assemblies.\u003c\/p\u003e\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\u003cp\u003eInstallation is performed by a licensed carpenter, door hardware specialist, or general contractor following the door manufacturer's fire label requirements. Before adjusting spring tension or closing speed, ensure the door is properly hung and all screws are fully seated. On UL-listed fire doors, do not modify the door or frame in any way that would void the fire label. Consult local building codes and the Authority Having Jurisdiction for fire door hardware requirements prior to installation.\u003c\/p\u003e\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eHinge Size\u003c\/strong\u003e: 4 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial\u003c\/strong\u003e: Cold rolled steel with stainless steel finish\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCorner Style\u003c\/strong\u003e: Square corners\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eClosing Speed\u003c\/strong\u003e: Adjustable\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSpring Tension\u003c\/strong\u003e: Adjustable\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFire Door Rating\u003c\/strong\u003e: UL Approved for fire doors\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePackage Quantity\u003c\/strong\u003e: 2 per package\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight\u003c\/strong\u003e: 1.7 pounds\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eStandard Information\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand\u003c\/strong\u003e: NATIONAL MFG\/SPECTRUM BRANDS HHI\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number\u003c\/strong\u003e: N350-819\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"NATIONAL HARDWARE","offers":[{"title":"Default Title","offer_id":51558337380658,"sku":"N350-819","price":56.92,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/cc2bc34a2bfee376567b1cfd57dcace5.jpg?v=1786409741","url":"https:\/\/voomisupply.com\/products\/national-mfg-n350-819-4-inch-ss-spring-door-hinge-ul-fire-door","provider":"Voomi Supply","version":"1.0","type":"link"}