For building footprints less than 10000 f² (930 m²) or where multiple suction pits are required. The smallest of the 3 radon cages this hot dipped galvanized cage is constructed from a rolled cylinder of expanded metal decking with a sheet metal top and bottom. It has an 18" diameter, is 6” tall and fitted with a welded insert ring for an easy and stable installation of the 4” exhaust pipe. This suction pit cage meets the prescriptive requirements for the current Alberta and National building code section 188.8.131.52 (1). This item may take up to 3 weeks for delivery. Ships Canada Post Expedited.