Round Duct Adapter AWENTA KO120-29 fi125/120mm – transition 125mm to 120mm

AWENTA KO120-29 round duct adapter provides a precise and reliable metal transition from 125 mm to 120 mm circular ducting. Designed for ventilation installations, the reducer ensures firm mechanical connection between ducts, fans, grilles and other circular components where a small diameter change is required. The adapter is intended for use in residential and light commercial air extraction and supply systems and helps maintain airflow continuity across mismatched fittings.

Advantages

The AWENTA metal adapter offers a tight fit and stable mechanical connection that reduces air leakage at the joint. Its rigid construction supports easy insertion and alignment of circular ducts and ventilation components. The simple geometry and smooth inner surface help preserve airflow characteristics and reduce turbulence at the transition. Installation and removal are straightforward, which speeds up maintenance and system modification tasks.

Suitable for

• Connecting 125 mm circular ducts to 120 mm fans or grilles
• Residential kitchen or bathroom extraction systems
• Light commercial ventilation and HVAC retrofit projects
• Temporary or permanent ductwork adjustments requiring a small diameter reduction

Key specifications

• Type: round duct reducer / adapter for circular ventilation ducts
• Inlet diameter: 125 mm (outer/nominal duct size)
• Outlet diameter: 120 mm (outer/nominal duct size)
• Material: metal construction suitable for ventilation use
• Shape: straight concentric transition between diameters

How to use

Measure and confirm the external diameters of the ducting and component to ensure compatibility with the 125 mm to 120 mm transition. Insert the larger end onto the 125 mm duct or sleeve and the smaller end onto the 120 mm component, aligning the adapter concentrically. Secure joints with appropriate clamps, screws or sealing tape as required by the installation practice to prevent air leakage. Verify that the connection is mechanically stable and does not obstruct airflow before restoring system operation.

Usage recommendations

For best results, use corrosion-resistant clamps or fasteners and apply duct sealing tape or mastic to reduce leakage. If the system includes flexible ducting, ensure the adapter is supported to avoid sagging or stress on the connection. Check local ventilation codes and manufacturer instructions for compatible mounting and sealing methods.