SRAM GX Eagle AXS Upgrade Kit - Rear Derailleur, Battery, Eagle AXS Controller w/ Clamp, Charger/Cord, Chain Gap Tool, Black SRAM GX Eagle XG-1275 Cassette - 12-Speed, 10-52t, Black, For XD Driver Body SRAM GX Eagle Chain - 12-Speed, 126 Links, Silver/Gray OPTIONAL Crankset, choose from drop down SRAM Eagle drivetrains are the only 1x drivetrains that are fully system engineered for optimal performance. Eagle drivetrains are designed, tested and proven to deliver the lightest, highest-performing, most durable systems for all riders on any trail.