Quarq DFour AXS DUB Power Meter Spider - 110 BCD 8-Bolt Crank Interface Black. DZero DUB SpiderSpider must be paired with a compatible Quarq DZero DUB crankset with an 8-bolt interface and SRAM DUB bottom bracketNot compatible with SRAMs 3-bolt direct mount interfaceDFour DUB is designed for Dura-Ace R9100 chainringsBluetooth low energy technology and ANT+ wireless data transferMagicZero technology automatically checks and recalibrates your power meter as you ride – no need to manually calibrateAxCad system provides no-magnet cadence dataUse the AXS app to easily update firmware and view power meter metricsMeasures power for both legs with +/- 1.5% accuracyUses a CR2032 battery that can be replaced without toolsOmniCal system allows you to swap chainrings without affecting accuracyIPX7 waterproof rating