Grundfos 98371278, Chamber Coupling, for use with Model CRN 5-2, CRN 5-3, CRN 5-4, CRN 5-5, CRN 5-6, CRN 5-7, CRN 5-8, CRN 5-9, CRN 5-10, CRN 5-11, CRN 5-12, CRN 5-13, CRN 5-14, CRN 5-15, CRN 5-16, CRN 5-18, CRN 5-20, CRN 5-22, CRN 5-24, Series CRN