{"product_id":"national-mfg-n350-785-3-5in-ss-spring-door-hinge-ul-fire","title":"National Mfg N350-785 3.5in Ss Spring Door Hinge Ul Fire","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\n\u003cp\u003eThe NATIONAL MFG\/SPECTRUM BRANDS HHI N350-785 is a 3.5-inch stainless steel spring-loaded door hinge designed for adjustable self-closing door applications. Manufactured from cold rolled steel with a stainless steel finish, this hinge provides both adjustable closing speed and adjustable spring tension, allowing installers to fine-tune door behavior after installation. The square-corner profile fits standard hinge cutouts without modification. It is UL approved for use on fire doors, making it suitable for code-required fire-rated door assemblies in residential and light commercial construction. Each package contains two hinges.\u003c\/p\u003e\n\u003cp\u003eThis hinge is used in applications where a door must self-close consistently, including fire-rated corridor doors, stairwell access doors, and utility room entries. The adjustable tension and closing speed make it well-suited for installations where door weight and swing resistance vary. It fits standard hinge cutouts, so it drops into existing mortises without additional prep work. Carpenters, general contractors, and facility maintenance professionals are the primary installers. The UL fire-door listing makes it appropriate wherever local building codes require self-closing hardware on fire-rated assemblies.\u003c\/p\u003e\n\u003ch4\u003eKey Features\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003eUL approved for fire-rated door assemblies\u003c\/li\u003e\n  \u003cli\u003eAdjustable closing speed for fine-tuned door control\u003c\/li\u003e\n  \u003cli\u003eAdjustable spring tension to accommodate varying door weights\u003c\/li\u003e\n  \u003cli\u003eFits standard hinge cutouts with square-corner profile — no mortise modification required\u003c\/li\u003e\n  \u003cli\u003eConstructed from cold rolled steel with stainless steel finish for corrosion resistance\u003c\/li\u003e\n  \u003cli\u003eSold as a package 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 new-installation self-closing hinge for standard 3.5-inch hinge cutout fire-rated and non-fire-rated doors in residential and light commercial applications.\u003c\/p\u003e\n\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\n\u003cp\u003eInstallation is typically performed by a carpenter, door hardware installer, or licensed general contractor. Ensure the door is properly supported and the frame is plumb and square before mounting. Adjust closing speed and spring tension only with the door hanging and hardware fully secured, using the adjustment tool or hex key appropriate to the hinge mechanism. Where fire-door ratings are required, verify the full assembly — door, frame, and hardware — meets the applicable local building and fire code requirements before sign-off.\u003c\/p\u003e\n\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHinge Size\u003c\/strong\u003e: 3.5 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\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePackage Quantity\u003c\/strong\u003e: 2 hinges\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWeight\u003c\/strong\u003e: 1.5 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: N350-785\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"NATIONAL HARDWARE","offers":[{"title":"Default Title","offer_id":51558763594034,"sku":"N350-785","price":71.49,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/dd29cf5517d36b768f19b7c76ce37cfa.jpg?v=1786419890","url":"https:\/\/voomisupply.com\/products\/national-mfg-n350-785-3-5in-ss-spring-door-hinge-ul-fire","provider":"Voomi Supply","version":"1.0","type":"link"}