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.-3D Power Measurement - 4iiii's patented 3D power measurement system measures multidimensional strain, so you can be confident that your unique pedal stroke is still measured accurately no matter your riding conditions.-Industry Leading Accuracy - Our +/- 1% accuracy isn’t just a claim, it’s been third party tested and validated by leading scientists and the Locomotion Lab at the University of Colorado.-Dual-Channel ANT+ & Bluetooth Smart - 4iiii Powermeters communicate their measurements over both the widely-used ANT+ and Bluetooth Smart radio standards.-3 Year Warranty - 4iiii Powermeters are waterproof, durable, and designed to be accurate and precise even in the harshest conditions. Because of this, we are happy to offer an industry-leading 3-year warranty.-Product is new, but may have minor cosmetic imperfections.