Shedding weight and size from previous generations, the PowerTap G3 Wireless Hub is lighter than ever, tipping the scales at a paltry 325 grams. Plus, its flange diameter has shrunk to 57 millimeters, making it feel just like a regular hub on the road. It also sports a low key matte black finish that's much more subdued than earlier versions. Other than its smaller size and stealth matte black finish, the G3 Hub retains 1. 5% accuracy for precise power measurement. For the design of the hub, PowerTap built the electronics into the end cap itself. This allows you to swap out end caps, should you experience a reading problem, instead of sending the entire wheel to PowerTap for analysis. Moreover, it allows for easier battery replacement, as a single CR2032 battery powers the G3. More than a just a power meter, the G3 Hub also measures speed and cadence with high accuracy. It communicates with ANT cycling computers for real time analysis of cycling statistics. Additionally, you can fit the G3 Hub with a Bluetooth Smart PowerCap sold separately that's compatible with popular smartphone apps, such as PowerTap mobile, Strava, and MapMyRide. Please note that the G3 Hub doesn't include a skewer, and it comes with a ShimanoSRAM or Campagnolo freehub body. It also includes instructions and a special tool for the hub's end cap.