These sturdy Airbricks By Timloc has been engineered to be easy to assemble. every Airbrick has clips on it that allow them to be stacked to create ‘9 x 9 inch’ and ‘9 x 6 inch’ sizes. Specially designed front grille to drastically reduce the amount of rain blown in by strong winds. They are created by injecting polypropylene (PP) that has been treated through UV stabilisation, into a mould. Features & Benefits Durable Decay resistant Available in 7 colours to suit your home and needs BS 5440 Pt 2 compliant Always use in conjunction with a Timloc telescopic underfloor ventilator, or cavity sleeve, depending on the application. Product Specification Colour: Blue/Black Area Per Airbrick: 6170mm2 Width: 230mm Height: 255mm Depth: 370mm