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 bushing. 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. All components are heat treated using RK's exclusive HIT (Heat Induction Transfer) process. 520MXZ5 has a maximum tensile strength rated at 8,500 lbs and is suitable for professional level 125cc to 500cc class racing.