The Vent-Axia Lo Carbon Centra HT Extractor Fan has an integral humidistat and timer. It is a dual speed continuous running fan for kitchens, utility rooms, bathrooms and toilet, with trickle speed selection at installation. The fan is automatically boosted by the built in humidistat or by a switched live input which activates the overrun timer (adjustable up to 30 minutes). Specification:Max Boost Air Extraction m3/hr: 54m3/hr Air Extraction L/s: 15 L/s Noise Level: 25.2dB(A) High Trickle Air Extraction m3/hr: 32.4m3/hr Air Extraction L/s: 9 L/s Noise Level: 15.5dB(A) Low Trickle Air Extraction m3/hr: 21.6m3/hr Air Extraction L/s: 6 L/s Noise Level: 10.8dB(A)