The PROX Steel Valve Kit is a top-tier product made from nitrided steel, which is micro-hardened to significantly reduce friction and wear. This results in a longer lifespan compared to original valves. It serves as an optimal replacement for short-lived titanium valves. The kit includes a specially weight-adjusted steel valve spring set made of chrome-vanadium, designed to withstand ultra-high RPMs. The kit can be installed without modifying any original parts, making it a convenient and robust upgrade for your YAMAHA engine. Experience enhanced performance and durability with this high-quality valve kit from PROX.