SRAM Force AXS Wide Left Crank Arm and Power Meter Spindle Assembly - 172.5mm, 12-Speed, DUB Spindle Interface, Iridescent Gray, D2Power measurement is a crucial part of training, so SRAM made it as easy as possible to upgrade your Force AXS ride with Quarq technology. DUB PWR takes the legendary reliability and accuracy of Quarq technology and inserts it into the crank spindle for clean integration that fits more bikes than ever. Its invisible technology that adds minimal weight and will help you get to the finish line faster. DUB PWR spindle based unit measures left side power