MXU series is the next generation of enduro/motocross racing chains featuring RK?s only technology of Ultra Thin Seal, U-Rings or UW-Rings, make possible to design a Sealed Chain withthe weight of a Non-Sealed Chain....
RK 520SO is a Classic ! The best choice if you are looking for an economical chain for motorcycle from 250cc to 400cc. Developed with Polaris ATV with Special Heat Treatment for Off-road Usage."
"8849
Designed for motocross racer, lighter weight but stronger chain compare to Heavy Duty Chain.non-sealed chainExcellent quality and cost performance for motocross racers 50-150cc."
"8800