When you need the absolute best from your training data, the accuracy and reliability of the RED XPLR AXS Power Meter is the way to go. The spider design uses a proprietary thread-on chainring mount system which allows us to reduce weight and increase stiffness without compromising the ability to swap rings. A dual sided power measurement system, it’s accurate to +/-1.5% even as weather conditions change, and boasts unbeatable battery life. Thread Mount design is light, stiff and accurate, and fits RED XPLR Thread Mount chainrings 38t-46t (Chainrings sold separately). Dual sided power measurement system, it’s accurate to +/-1.5% even as weather conditions change, and boasts unbeatable battery life (User replaceable CR2032 battery with 200-hour battery life). Bluetooth low energy technology and ANT+ wireless data transfer. MagicZero automatically checks and recalibrates your power meter as you ride. No cadence magnet required. 10K Temperature Compensation and Waterproof (IPX7 waterproof to 1 meter for 30 minutes). AXS enabled for easy monitoring and firmware updates. Includes 8 bolts and thread back up pin for chainring.