Simply Silent LV100 square grille fascia 4" 100mm extract fan with integral over-run timer featuring Ghost Air Movement Technology for quiet running. For use with an external switch or sensor. Is typically connected to the room lighting circuit. Fan continues to work after the fan is switched off. The timer is adjustable at installation from seconds to 30 minutes. Supplied with wall fitting kit comprising of outer grille, telescopic wall tube, gasket and foam strips. Supplied with 12V transformer.