The BB30 specific Quarq Riken AL Power Meter Crank Arms combine Quarq's industry leading power tracking capabilities with forged aluminum crank arms for wallet friendly satisfaction of all your power analysis needs. Track your training progress on the road, gravel, or cyclocross course and get the most out of every ride. To get the most accurate data, Quarq measures power at the spider in the heart of the crankset, capturing data at the transfer point between the crank arm and chainring. With a 1. 5% accuracy window, rest assured that you're getting the right readings to keep your training on track. Quarq has also addressed the pesky issue of temperature changes wreaking havoc on power measurement accuracy. The Riken AL comes with Quarq's 10K temperature compensation technology, the result of an extensive programming process that uses over 10,000 data points to facilitate accurate power measurement regardless of temperature. 10K temperature compensation is factored into every pedal stroke for continuous and consistent power readings. Tackle those high mountain passes and hot summer rides with confidence that your ride files will accurately reflect every watt you put into the pedals no need to stop and re zero along the way. The Riken AL measures cadence with an AxCad accelerometer, which means there won't be any unsightly magnets hanging off the frame to capture pedal rotations. An LED light on the face of the spider provides information for setup, and ANT ID lets the power meter recognize your specific head unit for quick installation and easy operation. We don't recommend taking these crank arms swimming, but in case you overshoot a corner and end up in a winding mountain stream, the Riken AL has an IPX7 waterproof rating, meaning they'll survive submersion in up to one meter of water for 30 minutes. This version of the Riken ALs is compatible only with BB30 bottom brackets, but all Riken AL crank arms are compatible with 10 speed Shimano chainrings...