Whether you’re a pro or simply training hard, PRECISION powermeters deliver industry-leading accuracy, highly dependable cadence data, 3D powermeter technology capable of measuring tri-axial strain on your crank arm. Designed to be durable and lightweight, compatible with ANT+ and Bluetooth head units, PRECISION helps you train harder and smarter. PRECISION Ride Ready comes installed on a new Shimano left crank arm (105, Ultegra, or Dura-Ace). These crank arms will fit bottom brackets using the Hollowtech ii interface. NOTE: check your frame clearance before ordering by downloading and printing the compatibility guide: Features: 3D powermeter technology (patent pending) measures tri-axial strain on your crank arm Accurate, consistent data Lightweight, compact design Battery status indicator via 4iiii app Compatible with ANT+, Bluetooth Smart head units, smartphones, and other 4iiii products User-friendly app and configurable rider compensation scale factor Easy setup and maintenance Specifications: Weight: 9 grams Data accuracy: +/- 1% error margin Battery life: 100+ riding hours on 2032 coin cell battery