White Diamond valves are CNC machined from one-piece forgings of EV8 Stainless Steel or Inconel-751 Electroplated with a 360º anode, to produce an even coat of the highest grade hard chrome finish Made in the USA - Yamaha YZ 426 F (2000, 2001, 2002); Yamaha WR 426 F (2002, 2001); Yamaha WR 400 F (1998, 1999, 2000); Yamaha YZ 400 F (1999, 1998)