{"product_id":"national-mfg-n350-850-4in-oil-rubbed-bronze-spring-door-hinge","title":"National Mfg N350-850 4in Oil Rubbed Bronze Spring Door Hinge","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\n\u003cp\u003eThe NATIONAL MFG\/SPECTRUM BRANDS HHI N350-850 is a 4-inch oil rubbed bronze spring-loaded door hinge designed for self-closing door applications. Manufactured from cold rolled steel, it features independently adjustable closing speed and tension, allowing installers to dial in the right close rate for the door weight and frequency of use. The hinge carries UL approval for fire door installations, making it a code-compliant choice where rated assemblies are required. It ships in a package quantity of two, covering a standard single-door installation. Carpenters, general contractors, and door hardware installers are the typical trades working with this product.\u003c\/p\u003e\n\u003cp\u003eThis hinge is suited for residential and light commercial interior door installations where a self-closing function is required. The 1\/4-inch radius round corners and standard hinge cutout dimensions allow it to drop into existing hinge mortises without modification in most cases. Its UL listing for fire doors makes it appropriate for rated corridor and stairwell doors in commercial occupancies where self-closing hardware is mandated by code. The oil rubbed bronze finish suits applications where a dark, matte hardware aesthetic is specified.\u003c\/p\u003e\n\u003ch4\u003eKey Features\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003eAdjustable closing speed allows field tuning to match door weight and use frequency\u003c\/li\u003e\n  \u003cli\u003eAdjustable spring tension for consistent self-closing performance over time\u003c\/li\u003e\n  \u003cli\u003eUL approved for fire door assemblies, supporting code-compliant rated installations\u003c\/li\u003e\n  \u003cli\u003eFits standard hinge cutout mortises without modification\u003c\/li\u003e\n  \u003cli\u003e1\/4-inch radius round corners for compatibility with standard door prep\u003c\/li\u003e\n  \u003cli\u003eCold rolled steel construction with oil rubbed bronze finish\u003c\/li\u003e\n  \u003cli\u003eSold as a pack of two hinges\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eCompatibility\u003c\/h4\u003e\n\u003cp\u003eDesigned as an OEM-style replacement or upgrade hinge for standard residential and light commercial doors with a 4-inch hinge mortise prep, including UL-listed fire door assemblies where self-closing hardware is required.\u003c\/p\u003e\n\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\n\u003cp\u003eInstallation is typically performed by a carpenter, door hardware installer, or general contractor. Before installation, confirm the door and frame mortises match the 4-inch hinge dimensions and 1\/4-inch corner radius. On fire-rated assemblies, verify that all components of the door assembly maintain the required UL listing and consult local building codes for self-closing hardware requirements. Adjust closing speed and tension using the hinge adjustment screws after the door is hung and hardware is fully fastened.\u003c\/p\u003e\n\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHinge Size\u003c\/strong\u003e: 4 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFinish\u003c\/strong\u003e: Oil Rubbed Bronze\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMaterial\u003c\/strong\u003e: Cold Rolled Steel\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCorner Radius\u003c\/strong\u003e: 1\/4 inch\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSpring Type\u003c\/strong\u003e: Adjustable closing speed and tension\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCertifications\u003c\/strong\u003e: UL Approved for Fire Doors\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePackage Quantity\u003c\/strong\u003e: 2\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWeight\u003c\/strong\u003e: 1.7 pounds\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: NATIONAL MFG\/SPECTRUM BRANDS HHI\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number\u003c\/strong\u003e: N350-850\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"NATIONAL HARDWARE","offers":[{"title":"Default Title","offer_id":51558775554354,"sku":"N350-850","price":43.13,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/7a45cf098f7d8ee8e4c61f1077532417.jpg?v=1786420228","url":"https:\/\/voomisupply.com\/products\/national-mfg-n350-850-4in-oil-rubbed-bronze-spring-door-hinge","provider":"Voomi Supply","version":"1.0","type":"link"}