Renthal 520 RR4 Race Chain (120 Links) (Gold) A highly specialized lightweight 520 sealed-ring chain developed exclusively for Superbike racing applications where a combination of lightweight and durability are a must. Utilizes Renthal's self-regulating seal (SRS) technology to increase service life. The specially developed self-regulating seal (SRS) ring is pre-loaded during assembly creating a spring effect. As the chain wears, conventional O-ring and X-rings loose their seal, however, the SRS ring has the ability to unload itself during use keeping a tighter seal against the side plates. This offers increased longevity as the specially formulated grease remains trapped around the critical pin and bushing area longer while also keeping dirt, water and other contaminants out.SRS ring technology enhances chain flexibility and offers smoother