Diamond 530Std Rear Chains 530Xlo O-Ring chain seals out abrasives and seals in dual lubrication with factory injected, heavy grade lubricant. O-ring lubrication keeps the chain lubricated and prevents premature elongation and contaminants out of the pin/bushing joint. Features oil-impregnated sintered steel bushings. Features: The chain of proven performance Shot-peened and factory pre-lubricated for maximum strength and long life Master Link is included Master Link Installation tool 6000365 strongly recommended for installation Made in USA