A Belter water hauling company that operates ice freighters between Saturn's rings and the stations of the Belt. The Canterbury, whose destruction triggers the events of the series, is a Pur'n'Kleen ship crewed by a skeleton complement running water to Ceres. The company represents the unglamorous backbone of Belt economics - essential, dangerous work done by expendable crews on ageing ships, generating profits that flow to inner-planet shareholders while Belters take the risks.