625 x 75 Supply/Return Air Grille for Round Duct

The ventilation grille for circular ducts (supply/return) attaches to a galvanized duct and is used for both fresh air intake and exhaust air extraction, with an adjustable airflow rate of 100 to 400 m³/h.

Dual-Flow Grill for Galvanized Ventilation Ducts

This dual-flow grille can be used in both supply and return air systems on a circular galvanized duct. It slides directly onto the duct without requiring major modifications to the system, making it a practical accessory for supplementing or repairing an existing ventilation system. The opening level is adjustable to control airflow according to your needs—a real advantage when balancing multiple points within the same system.

Technical Specifications

Usage and Compatibility

This supply/return grille is suitable for professional mechanical ventilation systems and building ventilation systems, whether in the food service industry, the service sector, or workshops—anywhere a circular galvanized duct with a diameter ranging from D200 to D400 mm needs to terminate in an adjustable air outlet or inlet. The adjustable opening allows airflow to be controlled between 100 and 400 m³/h,, providing a useful reference for balancing a system with multiple grilles or adjusting the airflow to a specific room.

Installation and Connection

The grille fits onto a circular galvanized duct of a compatible diameter without requiring complex drilling into the existing ductwork. As with any ventilation accessory, the upstream electrical connection (motor, housing) must be performed by a professional to maintain the warranty.

Things to Check Before Ordering

• Check the exact diameter of your duct: this grille covers the range from D200 to D400 mm; outside this range, it will not be suitable.
• Determine whether you need supply or exhaust airflow: the dual-flow grille handles both, but keep the overall balance of your system in mind.
• Estimate the airflow required for your space or system: the adjustable range of 100 to 400 m³/h must match your actual needs, which also depend on the number of elbows and the length of the ductwork.
• Checkthe availablespace (W 425 x H 75 mm) at the installation location, particularly where the duct exits the exterior wall or suspended ceiling.

Pair with

To extend or connect your system, check out our 2-meter rigid galvanized steel duct. Also explore our entire product line in the Ventilation Accessories category.