The PROX Steel Valve Kit is crafted from nitrided steel of the highest quality, which is micro-hardened to significantly reduce friction and wear. This engineering ensures an extended lifespan compared to original valves, making it an ideal replacement for the short-lived titanium valves. The kit includes a specially weight-adjusted chromium-vanadium steel valve spring set, designed for exceptional high RPM resistance. The best part is it can be installed without modifying any original parts!