Ultegra FC-R8100 12-Speed Crankset Arm Length:170mm The speed sensor 2 attaches

The speed sensor 2 attaches to the hub of either wheel and self-calibrates with your Edge cycling computer or compatible Garmin device to give you accurate speed and distance at all times — even without a head unit

Highly experienced backpackers will appreciate industry-leading comfort and ventilation—without the weight it often adds—making it the perfect pack for ultralight multiday adventures

Its Targeted Airflow Pattern mirrors the shape and position of a cyclist's body while riding

wrapped in flexible AmFIB softshell fabric to block wind and moisture

Ultegra FC-R8100 12-Speed Crankset Arm Length:170mm The speed sensor 2 attachesAn integral part of the Shimano Ultegra 12 speed road lineup, the FC R8100 crankset builds upon Shimano's legendary front shifting and transmission efficiency. With new refinements for seamless 12 speed shifting, the Ultegra crank is now offered in a wide variety of lengths, bringing performance and improved fit for smaller riders, triathletes, and riders with specific biomechanic requirements.