Cog Sizes: [11-30] 11, 12, 13, 14, 15, 16, 17, 19, 21, 24, 27, 30, [11-34] 11, 12, 13, 14, 15, 17, 19, 21, 24, 27, 30, 34 Cog Material: steel Freehub Type: HG Carrier Material: aluminum Claimed Weight: [11-30] 291g, [11-34] 345g 12 speeds of range make its way to the Shimano lineup with the Ultegra CS-R8100 12-Speed Cassette. This cassette utilizes 12 gears to keep the rations closer and pedaling action smoother up and down the cassette. Ultegra cassettes are made of steel to take on plenty of abuse and long miles.