GB420MXZ chains are made for the serious motocross racer looking for the lightest, strongest non O-ring chain GB420MXZ chains feature chrome-moly steel construction with seamless rollers and bushings, and oversized special alloy pins for added strength All components are heat-treated using RK's exclusive HIT (Heat Induction Transfer) process GB420MXZ racing chains are the strongest in their class giving you the best value-performance rating of any MX racing chain in the world today With a maximum tensile strength rated at 5000 foot pounds and weighing in at only 1.76 pounds, the GB420MXZ is ideal for professional level 50cc to 125cc open class racing