The Knut Bø Muro-Style 100 MHY is a 4-inch (Ø100 mm) bathroom extract fan with adjustable timer, adjustable hygrostat and integrated backdraft damper. Rated free-air flow is 95 m³/h and the fan starts automatically when humidity or manual demand exceeds the set threshold. It is intended for wall or ceiling mounting in bathrooms and utility rooms with standard 100 mm ducting.