The G935 Combination Cavity Sleeve fits into the back of Manthorpes G930 Airbrick to ventilate through a standard cavity or solid brick wall. The unit can be stacked to create a 9 x 6 and 9 x 9 alternative, and telescopes to fit cavity widths of 50mm to 100mm, with further extension possible through the addition of extra product units. The G935 also includes an integral wind baffle.For use with Manthorpe G930 air bricks. 6,600mm2. Black.