RK's NEW MXZ5 Supercross Racing chains are made for the serious supercross and motocross racer. MXZ5 chains feature chromoly steel construction with seamless rollers and bushings, with all components are heat treated using RK's exclusive HIT (Heat Induction Transfer) process. RK's reinforced Chromized pins drastically improve the wear resistance more than two times compared to normal non-sealed chains while absorbing shock loads from extreme jumps. 520MXZ5 has a maximum tensile strength rated at 8,500 lbs and is suitable for professional level 125cc to 500cc class racing. MXZ5 has a higher tensile strength and higher rigidity than its predecessor MXZ4 chain. 520MXZ5 will also come with a new less tacky grease which is less likely to attract dirt and debris.