Extensive R&D on all applications to provide high-performance components that last longer than OEM Black Diamond valves are one-piece forgings made from 21-4N high-performance stainless steel Trademarked Black Diamond treatment provides a stem that has a longer life capacity Keepers not included; use OEM keepers and bases, as noted All components made in the U.S.A.. VALVE INTAKE STD M8 17+
