Renthal (C391) 525-Pitch 130-Link R4 SRS Road Chain Renthal's R4 SRS Road chain is a specially developed sealed ring chain utilizing Renthal's Self Regulating Seal (SRS) technology to increase the service life of the chain in road applications As the chain wears, conventional O-rings and X-rings lose their seal integrity, whereas the SRS ring is designed to maintain itself during use, keeping a tighter seal against the side plates This offers increased longevity as the specially formulated grease remains incased around the critical pin and bushing area longer while also keeping dirt, water and other contaminants out All R4 SRS Road chains feature high alloy steel plates and pins, solid bushings and rollers, shot peened side plates for added strength, gold side plates, and a solid pin rivet link, matching the durability of the chain The Renthal special quad riveting process combined with thicker outer plates increases overall strength, and the chain is pre-stretched from the factory so less adjustment is needed during initial break in