From the Groco website: MODELS: IBV, FBV, FV and TWV GROCO's design for the imported valves series shown above specified a high-grade stainless steel valve stem. We have discovered that the stem material used in some of the valves manufactured between 2004 and 2006 may not have complied with our specifications. Valves with out-of-spec stems may not be suitable for salt-water use. Since the non-compliant silver color stems may fail when the valve is actuated we wish to have all such valves removed from service. GROCO will supply replacement valves at no charge. If you go to their website at: http://www.groco.net/ Then choose: <svc-bltn/cat-svc-bltn-2-08.htm>IBV-FBV Service Bulletin on the front page. Frank Burrows Destiny 1979 43' Viking MY Piney Narrows Chesapeake Bay