The Forterra Red Bank Square Hole Airbrick is made from clay material which makes it strong and durable. Rooms with a cavity wall under a wooden floor that contains a gas appliance which needs air bricks and cavity wall ducts to increase airflow and minimise the possibility of damp or accumulation of gases. This product measures 215 x 50 x 140mm (L x W x H) which is suitable for all the user's requirements. It contains the BES 6001 responsible sourcing certification for its quality. It weighs 3.40kg which is easy to handle.