Colonial Engineering CartridgeColonial Engineering’s replacement cartridges are designed for true union ball valves. The VCR Series fits Colonial Full-Block Series TUBVs. The CCR Series fits Nibco Chemtrol Tru-Bloc TUBVs. Both are designed and manufactured with face-to-face dimensions and body threads to engage with the union nuts of the existing installed valve. New face O-rings are included. The replacement cartridges are offered in PVC and CPVC with EPDM or FKM O-rings and PTFE seats. – colonialengineering.com