RK is the leading manufacturer of drive chains for motorcycles in Japan. For more than 40 years, RK has been supplying all well-known Japanese motorcycle manufacturers with original equipment. Even in racing, RK is the first choice of many teams in the MotoGP, the motocross or the Paris-Dakar Rally. RK XSO: This is an improved form of the O-ring chains. Due to the special shape of the X-rings the chain is sealed at four sealing points, the lubricant can not escape. In addition, the X-ring serves as an additional lubricant reservoir. The life of the chain is extended by about 30%. This technique has been further developed into the XW ring chain at RK. - X-ring chain - four sealing points - Lubricant can not escape - The service life is extended by 30% compared to the O-ring chain - Further development of the X-rings are the XW-rings