Rivet link RK Japan GB520MXU

Ultra Thin Seal Chain for Enduro
RK 520MXU is the lightest Sealed-Ring enduro/motocross chain available on the market today, 13.8g/link, only 0.1g/link heavier than RK 520MXZ4.
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, making it possible to design a Sealed Chain with
the weight of a Non-Sealed Chain. Seal Rings prevent debris from entering the chain,
which ensures efficient horsepower transmission from the engine to the
rear wheel throughout the chain life.