Lambro Industries 135 Galvanized Transition 4 in Round to Rect

Product Description

The LAMBRO INDUSTRIES 135 is a galvanized steel duct transition fitting designed to connect 4-inch round ductwork to 3.25-inch by 10-inch rectangular duct sections. This type of transition is a standard component in residential and light commercial ventilation systems, allowing installers to adapt between round and rectangular duct profiles without fabricating a custom fitting. It is constructed from galvanized steel for corrosion resistance and durability in typical duct environments. HVAC technicians and sheet metal installers use this fitting when routing supply or exhaust air through tight spaces where duct geometry must change.

The 135 is suited for rigid ductwork installations in kitchens, bathrooms, and general HVAC supply and exhaust applications where a round-to-rectangular transition is required. It is commonly used where a 4-inch round collar connects to a flat rectangular duct run, such as range hood exhaust routing or low-profile supply runs through cabinetry or wall cavities. The galvanized construction makes it appropriate for kitchen exhaust service where grease-laden air and moisture are present.

Key Features

• Transitions 4-inch round duct to 3.25-inch x 10-inch rectangular duct
• Galvanized steel construction for corrosion and moisture resistance
• Compatible with rigid ductwork systems
• Suitable for kitchen exhaust, range hood venting, and general HVAC applications
• Standard fitting geometry for straightforward field installation

Compatibility

Designed for use with rigid ductwork systems requiring a transition between 4-inch round and 3.25-inch x 10-inch rectangular duct profiles, including kitchen exhaust and general ventilation applications.

Installation Notes

Installation is typically performed by an HVAC technician or sheet metal installer. Secure all duct connections with sheet metal screws and seal joints with UL 181-rated foil tape or mastic per applicable mechanical codes before system startup. Verify that the fitting orientation matches the intended airflow direction before fastening. Do not compress or distort the fitting during installation, as dimensional changes will affect airflow and joint sealing.

Technical Specifications

• Product Type: Transition
• Round Size: 4 inches
• Rectangular Size: 3.25 inches x 10 inches
• Material: Galvanized Steel

Standard Information

• Brand: LAMBRO INDUSTRIES
• Manufacturer Part Number: 135