4iiii PRECISION Power Meter - Shimano Dura Ace R9100 Left Crank Arm 172.5mm | Accurate Cycling Power Measurement for Road Bikes & Training

Used to pace attacks up the Alpe D’Huez in the Tour de France and to hammer on the Queen K during the Ironman World Championships, the PRECISION Powermeter delivers industry leading accuracy and reliability when you need it most. Through our patented 3D Strain Gauge technology, you can be assured that the data you depend on will help lead you to your own Yellow Jersey.Packaged into a durable lightweight design and compatible with ANT+ and Bluetooth Smart headunits, PRECISION will help you train harder and smarter.A Ride Ready PRECISION includes and comes preinstalled on a brand-new Shimano crank arm of your choice. These crank arms will fit bottom brackets using the Hollowtech II interface.