Knut Bo ECO 150 AHT is a 6" wall- or ceiling-mounted extract fan fitted with an electric back-draught damper, a humidity sensor and a run-on timer. The fan starts automatically when humidity exceeds the setpoint or when the light circuit is switched, providing on-demand ventilation for bathrooms and utility rooms. It connects to a standard 150 mm duct and integrates with existing lighting or fan-only wiring.