Southwark Metal MF4A Aluminum Flexible Duct Uninsulated 4 Inches X 8 Feet

Product Description

The Southwark Metal MF4A is an uninsulated aluminum flexible duct designed for use in HVAC air distribution systems. It is built from a Type 100A special aluminum alloy that resists corrosion and metal fatigue, making it a dependable choice for both residential and light commercial ductwork installations. This flexible duct measures 4 inches in diameter and extends 8 feet in length, giving HVAC technicians a versatile, ready-to-install section of duct that can be routed around obstructions, connected to diffusers, or used as a branch run from a plenum box. The aluminum construction keeps the duct lightweight at 0.72 pounds, which simplifies handling and overhead installation. Because it is uninsulated, the MF4A is well suited for conditioned spaces where a vapor barrier or insulation wrap is not required, or where the installer will apply separate insulation per local code. The duct is rated for a maximum airflow velocity of 5000 feet per minute and a pressure rating of 12 inches water column both positive and negative, which covers a wide range of forced-air HVAC applications. The operating temperature range spans from -100 degrees Fahrenheit to 435 degrees Fahrenheit, making it compatible with both heating and cooling systems. Near-zero permeance means air leakage through the duct wall is minimal, which supports system efficiency and helps meet energy code requirements. The MF4A carries a UL Listed rating and meets UL Class O fire requirements. It is manufactured in the USA and is not subject to Proposition 65 restrictions. HVAC contractors, sheet metal workers, and mechanical installers will find this flexible duct a reliable component for branch duct runs, equipment connections, and air distribution work where flexibility and corrosion resistance are priorities.

• Type 100A special aluminum alloy construction resists corrosion and metal fatigue for long service life
• Rated for 5000 FPM maximum airflow and 12 inches WC positive and negative pressure
• UL Listed and UL Class O fire rated, manufactured in the USA

Product Highlights

The Southwark Metal MF4A delivers reliable, code-compliant flexible duct performance in a lightweight aluminum design suited for a wide range of HVAC air distribution applications. Its broad temperature range and near-zero permeance make it a practical choice for both heating and cooling system installations.

Product Information

Standard Information

• Brand: SOUTHWARK METAL
• Manufacturer Part Number: MF4A

Technical Specifications

• Material Composition: Type 100A special aluminum alloy
• Flex Type: Uninsulated
• Inside Diameter: 4 inches
• Flex Length: 8 feet
• Maximum Airflow: 5000 FPM
• Maximum Pressure: 12 inches WC positive and negative
• Operating Temperature Range: -100 degrees F to 435 degrees F
• Permeance: Near zero
• Fire Rating: UL Class O
• Approvals: UL Listed
• Country of Origin: USA
• Weight: 0.72 pounds
• Package Type: Box