320mm Stainless Steel Industrial Extractor Fan. Thanks to the durable metal casing, they can be mounted in window frames, doors, ventilation ducts or directly in the walls and operate as exhaust fans or supply air. Stainless Steel Plated Extractor Fan. Sound pressure level 60dB(A). A-390mm, B-390mm, C-300mm, D-300mm, W-165mm, Z-125mm, O-320mm.