The Vent-Axia Lo-Carbon Centra SELV Timer Pullcord Fan is a 100mm continuously running extract fan for kitchens, utility rooms, bathrooms and toilets, with a trickle speed to be selected at time of installation. The unit has a switch live or pullcord to boost together with an integral overrun timer which is adjustable up to thirty minutes. The integral digital air velocity sensor monitors airflow and maintains the preset extract flow rate of either 6 litres per second, 9 litres per second or 15 litres per second thus minimising energy use and noise levels.