Vectaires new SBAF two-speed range are ultra-slim, acoustic box fans specifically designed for installation into roof or ceiling voids to give continuous, energy efficient, quiet ventilation. The depth of the fan is slim, easily fitting  into the  ceiling void,  simplifying installation.  There is a choice of four extract capacities at which to set the lower speed.  The minimum (continuous running) capacity of the fan can be precisely adjusted to ensure that it suits the installation requirements, and the higher speed can  be controlled manually, or triggered by a PIR sensor, by a humidistat, by an Air Quality Sensor, or by a Thermostat.  The fans are available in five sizes to suit dwellings up to 1000 cubic metres.