SRAM RED AXS Power Meter Kit - 50/37t 2x12-Speed 8-Bolt Direct-Mount Polar Gray D1SRAM RED AXS Power Meter Kit 50 37t 2x12 Speed 8 Bolt Direct Mount Polar Gray D1. The SRAM RED AXS power meter kit is used to upgrade your RED AXS crankset to a power meter. Kit includes chainrings. AXS enabled for easy monitoring and firmware upgrades Power readings are accurate within + 1. 5% and arent affected by climate conditions during a ride Power balance measures left and right legs separately SRAM X SYNC wide tooth narrow tooth chainring