4iiii Precision Ultegra 6800 PowermeterDeveloped for increasing your performance, this crank arm powermeter gives you industry-leading accuracy on every training session. Whether you're competing on a pro-level or trying to beat your own personal goals, this it gives you durable, lightweight and dependable performance. It features 3D powermeter technology, which measures tri-axial strain on your crank arm. This means that you'll enjoy its accurate and consistent data as you clock up the miles on your road bike. Coming complete with ANT+ and Bluetooth compatibility, this model easily pairs up with your smartphone for simple setup and maintenance.Features: 3D powermeter technology (patent pending) measures tri-axial strain on your crank armAccurate, consistent dataLightweight, compact designBattery status indicator via 4iiii appCompatible with ANT+, Bluetooth Smart head units, smartphones, and other 4iiii productsUser-friendly app and configurable rider compensation scale factorEasy setup and maintenanceData accuracy: +/- 1% error marginBattery life: 100+ riding hours on 2032 coin cell batteryWeight: 9 gramsDisplay Compatibility: Android AppsCateEye CyclingEndomondoStravaWahoo Fitness: Workout TrackerPlus other apps supporting Bluetooth Smart/LE bike power devicesCATEYEStealth evo+Stealth 50Strada SmartPadrone SmartPadrone Smart+GarminEdge 500Edge 510Edge 520Edge 800Edge 810Edge 820Edge 1000Edge Explore 1000EpixForerunner 310XTForerunner 910XTForerunner 920XTfenix 2fenix 3fenix 3 HRSuuntoAmbit3 Sport (Bluetooth)iOS AppsBuy 4iiii Components from Chain Reaction Cycles, the World's Largest Online Bike Store.