Renthal's R4 SRS Road Chain is a specially developed sealed-ring chain using Renthal's SelfRegulating Seal (SRS) technology to increase the service life of the chain in road applications.The special SRS ring is pre-loaded during assembly creating a spring effect. As the chain wears,conventional O-rings and X-rings lose their seal; however, the SRS ring has the ability to unloaditself during use keeping a tighter seal against the side plates. This offers increased longevity asthe specially formulated grease remains trapped around the critical pin and bushing area longerwhile also keeping dirt, water and other contaminants out.