... and Phosphated and Black Oxide7.Hardnes:HRC56-HRC615F-6R flapper valve Cage Mdl.G CageFlapper Valve CageInvestment Casting Stainless Steel, Alloy SteelChecked ... sucessful fluoropolymer coating int the worlddramatically reduces crrosion and erosionMODEL "G"Flapper-Full FlowFalpper style valve features, and investment cast ... Standard: ASTM, BF,BS, JIS, UNI, ANSI, ISO etc. 5F-6R flapper valve Cage Mdl ...