Lambro Industries 3121 Aluminum Flexible Duct 4in X 8ft

Product Description

The LAMBRO INDUSTRIES 3121 is a 4-inch diameter aluminum flexible duct measuring 8 feet in length, designed for low-pressure air distribution in residential and light commercial HVAC applications. Constructed from aluminum, it offers the flexibility needed to route airflow around obstructions in tight spaces. The duct ships with 2 metal screw and plastic clamps included, allowing for secure connections at both ends without requiring a separate hardware run. HVAC technicians and sheet metal installers are the primary trades that work with this product.

This flexible duct section is suited for branch runs connecting a main trunk line or plenum to a supply or exhaust register. Its 4-inch diameter fits common residential duct sizing for bath exhaust fans, range hood venting, and HVAC supply runs. The 8-foot length provides enough reach for most standard branch connections. It is packaged individually and sold per unit.

Key Features

• Aluminum construction for durability and corrosion resistance in air distribution systems
• 4-inch inner diameter sized for common residential and light commercial branch duct runs
• 8-foot length suitable for typical branch connections without splicing
• Includes 2 metal screw and plastic clamps for immediate installation without additional hardware
• Flexible design allows routing around framing, joists, and other obstructions

Compatibility

Designed as an OEM-style replacement or standard installation component for 4-inch flexible duct applications in residential and light commercial HVAC, bath exhaust, and ventilation systems.

Installation Notes

Installation is performed by licensed HVAC technicians or qualified sheet metal workers. Shut down the air handling unit and confirm the system is de-energized before making duct connections. Secure each end of the flexible duct with the included clamps and verify there are no sharp bends or kinks that would restrict airflow. Follow local mechanical codes and ASHRAE guidelines for maximum flex duct run lengths and bend radius requirements.

Technical Specifications

• Diameter: 4 inches
• Length: 8 feet
• Material: Aluminum
• Included Hardware: 2 metal screw and plastic clamps
• Weight: 9.45 pounds
• Unit of Measure: Each
• Package Quantity: 9

Standard Information

• Brand: LAMBRO INDUSTRIES
• Manufacturer Part Number: 3121