The CAVHEXT3 is a telescope plastic cavity wall sleeve most commonly used inconjunction with the METIMP adaptor to connect it to imperial 9×3 air bricks.
At one end, the sleeve connects to an external air brick and allows air to flow in or out of a room via a 10×4 inch daisy grille on the inside (DAY104) or under the floor boards for sub floor ventilation. Duct tape may be required to connect imperial air bricks either with or without the metric to imperial although tape is unlikely to be required if connecting to metric airbricks. The CAVHEXT3 can be combined with CAV3 or another CAVHEXT3 for creating ducting in particular deep walls and can also be used with the PER to create a periscope duct. Should the duct need to be shortened it is best done using a bench circular saw although if not available it can be cut on site with a hacksaw.