6 to 4 Inch Duct Reducer/Increaser, Male-Fit Round Adapter, Plastic Reducer And Increaser, Duct Connector for Indoor HVAC and Ventilation Systems, Lightweight Round Air Vent Fitting

The ECOPRO VENT plastic duct reducer / increaser is a reliable solution for connecting different diameter round air ducts in indoor HVAC and ventilation systems. Designed to support smooth airflow transitions, this duct adapter helps maintain proper air movement and system efficiency when reducing or increasing duct size in residential and commercial installations. Manufactured from durable lightweight plastic, this HVAC duct fitting provides a corrosion-resistant alternative to traditional metal connectors. The rigid construction is suitable for long-term indoor use and performs reliably in air duct, vent pipe, and ventilation system installations where accurate sizing and dependable connections are essential. Each round duct connector features a stepped design with integrated rim stops that help prevent ducts from sliding too far over the fitting. Both ends are male fit and designed to insert securely inside compatible round ducting, ensuring proper alignment and stable positioning during installation. The plastic duct reducer installs without glue or adhesive and can be secured with clamps if additional holding strength is required. This plastic duct adapter is intended for indoor HVAC systems, air ventilation ducts, and general air duct connections in residential and commercial interiors. It operates within a temperature range of -5 °C to 14 °F to 158 °F (-10 °C to +70 °C ) and is not recommended for high-heat, outdoor, flue, stove, furnace, or combustion-related installations. Ideal for HVAC upgrades, ventilation maintenance, and new ductwork projects requiring a clean and efficient duct size transition.

• PRECISE SIZE TRANSITION: 6 to 4 inch duct adapter with stepped design. Diameter 5.87 Inch on the larger side and 3.89 Inch on the smaller side. Insertion depth 1.18 Inch. Designed for accurate indoor duct connections.
• LIGHTWEIGHT PLASTIC CONSTRUCTION: Made from lightweight plastic material suitable for indoor HVAC duct fittings. This reducer resists moisture and corrosion, making it ideal for long-term use in ventilation systems and indoor air duct installations.
• FUNCTIONAL AIRFLOW CONNECTION: Duct adapter provides a smooth airflow transition between duct sizes while reducing turbulence at connection points. INTEGRATED RIM: It acts as a stop edge to prevent ducts from sliding too far over the connector, helping maintain proper positioning during installation.
• EASY INSTALLATION WITHOUT ADHESIVE: Plastic duct connector installs easily without glue or adhesive. Both ends feature a male fit that inserts inside compatible round ducting. Clamps may be used for additional holding strength in HVAC duct connections. Suitable for DIY and professional installations.
• INDOOR HVAC APPLICATION: This plastic reducer is Intended for indoor HVAC systems, air ventilation ducts, round vent connections, and general air duct installations in residential and commercial interiors. Operating temperature range 14 °F to 158 °F (-10 °C to +70 °C ). Not recommended for high-heat or outdoor installations.