Rytons Cowl 9×3 Exclusive to i-sells made by Rytons. Surface-mounted cover for 9 x 3 inch openings, air bricks, grilles and vents. Size: 255mm L x 96mm H x 44mm D. Free Area: 8700mm² (87cm²) per unit. Installation: First, check the free air space of the cowl exceeds the air space required by the covered opening, air brick, grille or vent. Fix the cowl to the brickwork through the pre-formed holes in the flange. Protects against excessive weather conditions. Alleviates air blasts through the cavity. Textured roughcast finish. U.V. stabilised to slow down the effects of sunlight. BBA approved – your independent assurance that the product meets building regulations and standards and will last.