4-arm, without Chainrings, black 11-speed compatible, only suitable for DUB Cranksets with 8-bolt mounting, for Shimano Dura Ace 9100, Bluetooth and ANT+ wireless technology, IPX7 water protection, accuracy: +/- 1.5%, dual-sided measurement, MagicZero for automatic calibration, tool-free battery change (CR2032) The QUARQ crank spider Powermeter "DFour" is a high-performance measuring system for Shimano Dura Ace 9100 Chainrings. With a 4-arm design made of black aluminum, 11-speed compatibility, and an 8-bolt mounting, it is exclusively suitable for DUB Cranksets. The dual-sided measurement provides precise values with an accuracy of ±1.5%. Thanks to Bluetooth and ANT+, data transfer is seamless. MagicZero ensures automatic calibration, while the tool-free battery change with CR2032 offers maximum user-friendliness. IPX7 water protection completes the system for demanding training conditions. Number of chainrings none Main color black System compatibility 11-speed Type/kind Accessories Sram Article number: 721178 EAN code: 710845839443