Soss 418US4 Heavy Duty Fire Rated Invisible Hinge Satin Brass

Product Description

The SOSS 418US4 is a heavy-duty, fire-rated invisible hinge designed for 1-3/4 inch thick doors in commercial and residential applications. Constructed from alloy steel with a satin brass finish, this hinge installs fully concealed within the door and frame, leaving no exposed knuckles or barrels when the door is closed. At 2.45 pounds, it is built to handle demanding door cycles without sacrificing a clean finished appearance. Licensed door hardware installers and finish carpenters are the primary trades who spec and install this hinge on hollow-metal and solid-core wood door assemblies.

The 418US4 is suited for 1-3/4 inch doors in commercial office entries, healthcare corridors, hospitality interiors, and high-end residential applications where a flush, hardware-free door face is required. Its fire-rated construction makes it an appropriate choice for assemblies where code-compliant fire-door hardware is mandated. The satin brass finish coordinates with standard commercial and architectural hardware sets.

Key Features

• Fully invisible when door is closed — no exposed hinge barrel or knuckles
• Fire-rated construction for use on rated door assemblies
• Heavy-duty alloy steel body rated for high-cycle commercial use
• Satin brass finish for architectural hardware compatibility
• Designed for 1-3/4 inch door thickness
• Sold individually (EA) for flexible quantity ordering

Compatibility

Designed as an OEM-style replacement or new-installation invisible hinge for 1-3/4 inch fire-rated and standard door assemblies requiring concealed hinge hardware.

Installation Notes

Installation requires precise mortising into both the door edge and the frame jamb; a router with a hinge template sized for this model is the standard method. Power down any electrified hardware and ensure the door assembly is properly supported before removing existing hardware. Fire-rated door assemblies must remain compliant with applicable building and fire codes — confirm the hinge is listed for the specific door and frame assembly rating before installation. Consult the authority having jurisdiction if substituting hardware on a labeled fire door.

WARNING: This product can expose you to chemicals including lead, which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.