passive air vent . anti draught , anti insect , anti mould , anti light 150 mm x 150 mm . white or brown . please state when buying in notes which colour required . with a new drain filter membrane core to remove 1 litre of water per 24 hour s approximate , the diameter of the tube is 100mm and the 350 mm tube can be cut to required length ...THE INNER CORE IS A MAN MADE FILTER MATERIAL USED IN AIR FILTERS AND HUMIDIFIERS FOR THE VENTILATION AND AIR CONDITIONING INDUSTRY FOR VENT SYSTEMS. THIS CAN BE REMOVED AFTER YEARS..WASHED THROUGH WITH COLD WATER . THEN PUT BACK INTO VENT UNIT.
