Now available as a spider by itself as an easy upgrade for existing cranks. The Dfour model offers enhanced data transfer & frame fit compatibility. Compatible with these non-power meter cranks: Quarq Prime & SRAM Red BB386EVO (not compatible with Quarq Elsa R cranks). Compatible with these power meter cranks: Quarq Elsa RS, Quarq Riken Al, Quarq Riken R (produced July 2015 & later), SRAM XX1, 2016 & later SRAM Red power meter cranks (Red e Tap graphics).