Manthorpe Core Drill Ventilator with Anti Draught Baffle Brown Hooded Cowl 5 Inch 127mm x 350mm To increase the air flow in a room to eliminate condensation for heat producing appliances. Ventilation for heating and gas appliances. Simply core drill through wall and place vents internally and externally. Aesthetically pleasing and simple to install modular system. 10,000mm² of airflow without draught baffle. 7,000mm² effective airflow with baffle. Meets requirements for British Gas. Other colours and vent styles available in our shop.Dimensions External Cowl : 160mm x 190mm Internal vent : 160mm x 160mm Core Tube length : 127mm Dia x 350mm Core tube can be cut to accommodate wall thickness 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 100cm² 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 100cm², it is only available in white. For situations where the total wall thickness exceeds 350mm, a 1,000mm pipe duct can be purchased separately.