SHIMANO ULTEGRA HOLOTECH II Crankset 2x12 Speed FC-R8100 ULTEGRAs new FC-R8100 Crankset offers a wider selection of crank lengths while maintaining the traditional quick and accurate front shifting and efficient power transmission. With the ability to choose between 160mm to 175mm crank lengths, it is also suitable for petite riders, triathletes and cyclists seeking shorter crank lengths. Features Optimized for rigidity, strength, weight, and rotational performance Hollow Glide construction maintains strength while reducing weight for better power transfer and faster precise front shifting.