SRAM XX/XX SL Eagle T-Type AXS Power Meter Spider - For Use with Thread Mount Chainrings, 8-Bolt Direct Mount, Black, D1The XX SL Eagle AXS Transmission Power Meter records and delivers live, accurate power readings to your head unit. Utilizing an all new spider based design, this is SRAM's most accurate, high performing power meter. The spider design uses a proprietary thread on chainring mount system which has allows reduced weight without compromising reliability. A dual sided power measurement system calculates total watts, it's subtle, lightweight, and boasts