Sealed Motocross: MXU is the lightest sealed-ring motocross chain available on the market today. Made for the professional motocross racer, GB520MXU is the next generation of motocross racing chains featuring RK's new UW-sealing rings. MXU chains are designed to provide the most consistent power delivery and increased chain life. All components are heat treated using Rk's exclusive HIT (Heat Induction Transfer) process. MXU has a maximum tensile strength rated at 9,000 foot pounds, weighs a mere 3.0 lbs for 100 links and can handle any MX race application from 125 to 500ccs.