T.M. Designworks PowerLip Chain Roller Kit - Yellow ZDK-RMZ-YLThe Powerlip chain roller is the only specific fit chain roller on the market Each roller is engineered and molded from a low friction custom plastic material The roller size and Powerlip offset are race tested to improve drive chain power and reduce chain plate wear The sealed bearings are ABEC certified, with special racing grease Kit with two rollers (for upper and lower mounting locations) comes with replacement bolts, nuts and shimming washers