The Manthorpe G930 Airbrick has been designed to provide high levels of ventilation into cavity walls and under floor voids. The brick incorporates a front mounted grille with water deflectors. A mortar key around the edge of the airbrick ensures it can be securely fixed to the building fabric and a clip together facility provides a choice of ventilation sizes. The product is suitable for use with gas appliances. Please note the colour shown in the image is only for illustration purposes. Features 6,450mm2 of airflow per 9 inch x 3 inch airbrick. Can be stacked together to create 9 inch x 6 inch and 9 inch x 9 inch combinations. Moulded in mortar key. Available in various colours to suit different substrates.