Power is an important metric to measure while you're riding. You'll be able to know if you're working too hard or not working hard enough on your ride. The SRAM Red & Force AXS Power Meter Spider is AXS enabled for easy monitoring and firmware upgrades. The power meter is both Bluetooth Low Energy and ANT+ compatible and the power readings are accurate within +/-1.5% and aren't affected by things like climate while you're riding. The power balance measures left and right legs separately and the meter uses CR2032 watch batteries that last for up to 200 riding hours.