Chain EK 530SR O-Ring 122 Link SR 500 The EK Chains O-Ring Chain is a value-priced O-ring chain that doesnt compromise on quality or durability, with such features as solid bushings, solid rollers and high-tech heat-treated steel alloys. All EK Chains motocross chains utilize our CRH pin treatment which provides an extremely hard outside coating and softer inside to increase strength and reduce chain wear. Exclusive to EK Chains, the Chromium Carbide pin surface coating also offers superior impact and shock absorption while reducing oxidation caused by natural elements.