Shimano ultegra 6600 10 speed chainhyperglide hg series 10 speed compatible chain recommended for ultegra drivetrains features hg technology has chamfered inner plates to optimise shifting performance on hg sprockets durability is assured through a chromising treatment on link pins and the heat treatment of rollers pins and plates mushrooming of the pins gives unsurpassed side plate retention enabling the chain to far exceed the bsiso standard for breaking force 588mm chain width opti