The Helios Fans WSG 40/20 is a wall-mounted grille designed to protect intake and exhaust air openings from the intrusion of rain, snow, and animals. Sized to match Helios duct fans, it fits directly into the cross-sectional area of the ducting. The grille is constructed from durable extruded aluminium with a natural anodised finish, ensuring strength and resistance to corrosion. It features fixed louvres spaced at 65 mm intervals for optimal airflow. A protective mesh grill made from galvanised sheet steel with a 16 mm mesh width is positioned behind the louvres, offering added protection without restricting ventilation.