Mm Manufacturing 641R6-8X4X5 Insulated Register Box R-6

Product Description

The MM Manufacturing 641R6-8X4X5 is a standard-size insulated register box designed for residential and light commercial HVAC duct systems. The interior is lined with 1.5 inches of ductliner insulation, delivering an R-6 thermal rating that reduces heat transfer and limits condensation on the box exterior. The unit stands 4 inches tall and includes an integrated snap-rail flange for fast, secure register attachment. HVAC installers use this box where a ducted supply or return opening terminates at a floor, ceiling, or wall register.

This register box suits new construction and retrofit applications in residential forced-air systems. The snap-rail flange design speeds up register seating without additional hardware, making it a practical choice for high-volume residential installs or single-replacement service calls. The R-6 insulation lining is suited for unconditioned spaces such as crawlspaces, attics, and exterior wall cavities where thermal and condensation control are required.

Key Features

• 1.5-inch ductliner insulation provides R-6 thermal rating
• Snap-rail flange allows tool-free register attachment
• 4-inch depth accommodates standard floor and ceiling register openings
• Standard size format fits common duct boot rough-in dimensions
• Insulated construction reduces condensation risk in unconditioned spaces

Compatibility

Designed as an OEM-style replacement or new-construction register box for residential and light commercial forced-air duct systems requiring an R-6 insulated terminal box with snap-rail flange.

Installation Notes

Installation is performed by licensed HVAC technicians or sheet metal contractors. Power down the air handling unit and close the system dampers before connecting to existing ductwork. Seal all joints with approved duct mastic or foil tape per local mechanical code requirements. Do not compress the ductliner insulation during installation, as compression reduces the effective R-value.

Technical Specifications

• Insulation R-Value: R-6
• Ductliner Thickness: 1.5 inches
• Box Depth: 4 inches
• Length: 10 inches
• Width: 6 inches
• Height: 6.75 inches
• Weight: 1.35 pounds
• Flange Type: Snap-Rail

Standard Information

• Brand: MM Manufacturing
• Manufacturer Part Number: 641R6-8X4X5