Titanium Exhaust Valve. The ProX titanium valves are manufactured to high quality standards. High tech Ti3al alloy is forged in one-piece for extra strength while the material offers superior material properties at high temperatures, the additional CrN coating offers extreme surface hardness and creates considerably lower friction. The ProX titanium valves do exceed O.E. specifications in dimensions and reliability. High tech Ti3al alloy is forged in one-piece for extra strength while the material offers superior material properties at high temperatures. The additional CrN coating offers extreme surface hardness and creates considerably lower friction. ProX titanium valves exceed O.E. specifications in dimensions and reliability, and are manufactured to highest quality standards. All valves sold each.