4-arm, 104 mm BCD, no chainrings, black 12-/11-speed compatible. Only suitable for chainsets with 8-bolt mounting, Bluetooth and ANT+ wireless technology, IPX7 water protection, Accuracy: +/- 1.5%, dual-sided measurement, MagicZero for automatic calibration, tool-free battery replacement (CR2032) Number of chainrings none Accessory type Main colour black System compatibility 11-speed, 12-speed These spiders can only be used on the SRAM XX1 Crankset. The spider does not fit standard SRAM MTB cranksets. SRAM Article number: 721179 EAN code: 710845839450