Wisecos stainless steel valves are made from premium materials and manufactured to the highest quality specifications. A one-piece, forged construction offers high strength and fatigue properties. Chromium nitride coating offering surface hardness and wear resistance. Each design is a drop-in application and requires no piston or head modifications, and will work with stock springs and valve-train. Fits: Yamaha YFM350 Warrior 1987-2004, YFM350R Raptor 2005-2010, YFM350 Wolverine 1995-2008, YFM350 Bruin/Grizzly 2004-2010.