Automatic Backdraft Protection – Gravity-operated louvers open with exhaust airflow and close automatically to prevent backdrafts, cold air ingress, rain, and snow entering your system Designed for External Ventilation – Ideal for HVAC exhaust points on exterior walls, including plant rooms, generators, garages, workshops, and ducted ventilation systems Durable Anodized Aluminium Build – Manufactured from high-quality aluminium with a robust 2mm frame and thick louvers for long-lasting performance and corrosion resistance Non-Fixed Gravity Louvres – Not adjustable or fixed open; blades respond dynamically to airflow for efficient ventilation while maintaining protection when not in use Easy Installation & Standard Sizing – Sized by neck dimension to fit duct openings; install easily using self-tapping screws (not included) directly into wall or mounting surface