Genuine Shimano replacement part 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 BS/ISO standard for breaking force 6.57 mm chain width, optimised for 9-speed Super Narrow HG drivetrains Corrosion-resistant grey finish on inner and outer plates Zinc-alloy silver finish on outer plates, and grey finish on inner plates increase corrosion resistance 116 links, 310 grams .