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.Key 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.