Doulton W9381100 Rio2000 BB System The W9381100 Rios unique 6 element filter module is designed to be fitted to the main water supply to supply large volumes of healthy, clean water The Doulton W9381100 Rio 2000 Whole House Filtration System features- No power required and low running costs Doulton Sterasyl is a highly efficient ceramic micro filter which provides genuine sub micronfiltration of drinking water