SRAM RED AXS 2x Power Meter Chainring Kit - 48/35t, 2x12-Speed, 8-Bolt, Direct Mount, Black/Silver, E1It's the ultimate in integrated power measurement. The RED AXS power meter kit adds Quarq technology to SRAM's one piece chainrings for the lightest, stiffest, and most accurate power package available. A 13 tooth delta on all chainring pairs ensures precise shifting for any setup, as well as a less dramatic change in cadence during front shifts. Combined with our most durable chainrings ever, it's an unbeatable combination. X Range gearing technology