This version of the SRM Power Meter features a larger diameter than Shimano's 7900 version. This adequately accommodates the larger FC 9000 crankset. In addition to allowing the crankset to fit properly, the new platform also provides more accurate measurement of the offset forces and torque patterns for your left versus right leg, which means more accurate overall power measurements. The wider diameter holds two batteries, which equates to almost 3,000 hours of use before needing to be recharged. SRM uses its tried and true eight strain gauges for measuring data. The 9000 Power Meter features an accuracy of 2. 0% between 30 and 255 rpm, with a wattage range between 0 and 4096 watts, for that wild finishing sprint. The FC 9000 crank is the same Dura Ace crank being touted for its versatility. You're able to run compact or standard rings on the same spider. Thanks in part to the four arm design, it is also lighter than, but just as stiff as, its predecessor. It uses Shimano's Hollowtech II and Hollowglide technology to create a stiff yet lightweight design with an unrivaled weight to stiffness ratio.