SRAM GX Eagle AXS Upgrade Kit – Rear Derailleur Battery Eagle AXS Controller w/ Clamp Charger/Cord Chain Gap Tool Black. The SRAM GX Eagle AXS upgrade kit is your entry point into wireless drivetrain simplicity. Compatible with any of the SRAM Eagle ecosystem cassettes and crank arms the upgrade kit allows you to experience AXS without needing to buy an entire groupset provided you already are using Eagle products. No matter if you are looking to upgrade your ride or looking for great value replacement parts look no further than the GX Eagle AXS upgrade kit.