Soss 303CUS4 Invisible Hinge Satin Brass Medium Duty

Product Description

The SOSS / UIP ALLEGION 303CUS4 is a medium-duty invisible hinge designed to conceal itself fully within the door and frame when closed, leaving no exposed hardware on the face of the door. Finished in satin brass, it measures approximately 0.5 inches in height profile and 1.52 inches in width, sized specifically for doors with a thickness of approximately 0.69 inches (11/16 inches). Sold as a pair, this hinge suits interior door applications where a clean, hardware-free appearance is the priority. Installation requires a routed mortise pocket in both the door edge and the frame jamb.

The 303CUS4 is intended for medium-duty residential and light commercial interior doors where concealed hinging is required. It is well suited for custom cabinetry doors, passage doors, and architectural millwork applications where traditional butt hinges or surface-mounted hinges would compromise the finished look. The satin brass finish integrates cleanly with brass and gold-tone hardware sets. Units are sold in pairs, with a case quantity of 10 pairs available for larger projects.

Key Features

• Fully invisible when door is closed — no exposed knuckles or barrels on the face
• Medium-duty construction suited for standard interior passage doors approximately 0.69 inches thick
• Satin brass finish for compatibility with warm-tone hardware sets
• Compact profile: approximately 0.5 inches height, 1.52 inches width
• Sold as a pair (PR) for single-door installation
• Requires mortise routing in door edge and frame jamb for proper seating

Compatibility

Designed as an OEM-style invisible hinge replacement or new installation for interior doors with a door thickness of approximately 0.69 inches (11/16 inches) requiring a concealed hinge solution.

Installation Notes

Installation is performed by a finish carpenter or door hardware installer. Power down any automatic door operators before servicing the door assembly. Proper mortise routing in both the door edge and the frame jamb is required for flush seating — use a router or chisel set sized to the hinge leaf dimensions. Follow applicable building codes for door hardware in commercial applications.