... wearing between the pin-shaftand the sleeve. The "O" ring will greatly reduce the wearing and thus prolongthe ... It is most suitable for high-speedrunning.Our brand O-ring chain be recommend the no. 1 in Chinese ... chain association, berecommend to worldwide.1) Model: 35,40,50,60,80, ... Blue, Brown, Nickel,Color, Copper3) Packing: Industry packing O-ring Roller Chains for machines