Shimano altus hg40 678 speed chainhyperglide hg series 6 7 or 8 speed compatible chain recommended for altus and aliviostx drivetrains featureshg technology has chamfered inner plates to optimise shifting performance on hg sprocketsdurability is assured through the heat treatment of rollers pins and platesmushrooming of the pins gives unsurpassed side plate retention enabling the chain to far exceed the bsiso standard for breaking force7 3mm chain width optimised for 7 and 8 speed