For 2015, Shimano's 105 groupset got a few high-profile upgrades. It's gone to 11-speed, and now has many of the same crankset technologies seen in Dura-Ace and Ultegra. As you'd expect, changes to the cassette and crankset also necessitate changes to the chain that connects them. Shimano designed the new SLX/105 CN-HG601 11-Speed Chain as one of the new 11-speed chains from the Japanese manufacturer. The HG601 differs from the HG901 in that it uses solid pins instead of hollow. This amounts to a weight gain of about 0. 08 grams per link, but it also adds to the durability and reliability of the only chain worthy of being associated with the hardworking 105 group. Despite its slightly higher weight, it does receive the same revolutionary new Sil-Tec ultra-low friction treatment as its more expensive sibling. Sil-Tec reduces friction dramatically while also increasing the chain's longevity and decreasing noise. Please note that while it's specifically designed for the new 11-speed 105 5800 and SLX M7000 groupsets, the CN-HG601 chain is also compatible with all of Shimano's 11-speed drivetrains.