Manthorpe G900 5" Core Ventilator Brown The Manthorpe 5" Core Drill Vent G900 is designed for use when ventilating a gas appliance, but can also be used for general through wall ventilation. The vent can easily be fitted in both refurbishment and new build situations with the use of a 5" (127mm) diameter core drill. The kit includes a cowl vent for exterior use, a louvre grille for inside, a 350mm length of pipe duct and an optional anti-draught baffle. This baffle reduces the airflow and also the feel of a draught through the vent. The external cowl minimises uncomfortable draughts, reduces noise and light from outside the property and acts as a barrier against wind driven rain whilst providing a free area of 100cm and is available in both brown and terracotta. The Louvre fits on the internal wall and, similarly to the cowl, reduces draughts, noise and light penetration, while providing a free area of 100cm, it is only available in white. 10,000mm of airflow without draught baffle 7,000mm effective airflow with baffle Ventilate gas appliances (Image Shows Colour Brown)