The new, high-performance, exceptional ZR series chains take a big step forward with our new, patented Z40 seal rings. This new generation of rings, which feature a special-design conical shape on their inner side, are the result of the evolution of the previous X-Ring and Z-Ring designs. Maximum technology and advantages: ? Patented Z section ? The Z-Ring deforms when assembled, creating a spring effect that produces a long lasting seal ? The special Z-Ring section enhances chain flexibility and smooth operation ? The conical section of the Z-Ring provides accurate positioning on the bushing ? The lubricant is trapped between the plates and the lobes of the Z-Ring, keeping the Z-Ring lubricated and prolonging its life.