This is the ultimate in integrated power measurement. The RED AXS power meter kit adds Quarq technology to our RED chainrings for the lightest, stiffest, most accurate power meter available. A 13-tooth difference on all chainrings ensures precise shifting for any setup, as well as a less dramatic change in cadence during front shifts. Combined with our most durable chainrings ever, it's an unbeatable combination. The power meter is fully integrated into the chainring. It measures power from both crank arms and is highly accurate with a variance of only 1.5%.