Shimano 105 CS-R7101 12-Speed 11-34T Cassette delivers smooth, efficient shifting for road cycling, helping you tackle flats and climbs. Featuring Hyperglide+ 12-speed sprockets on a lightweight alloy carrier, this cassette reduces weight without losing rigidity. Drilled sprockets boost performance, and the nickel-plated finish resists corrosion. Compatible with HG 12-speed chains. Buy your bike gears at Halfords, the UK's largest bike accessories retailer.