If your bike is already equipped with a SRAM Eagle drivetrain, the X01 Eagle AXS Upgrade Kit allows you to make the switch to wireless electronic shifting without needing to buy the entire AXS groupset. The kit includes the XO1 Eagle AXS derailleur with battery, the Eagle AXS shifter (SRAM calls it the Controller), and a battery charger with charging cable. These components are all you need to make the switch, which means you can continue using your existing Eagle cranks, cassette, and chain to save yourself a bit of extra cash on the upgrade. If you're reading this then you're probably debating why you should make the switch to electronic shifting. Doesn't that make my bike more complex and harder to maintain? The truth is, it's actually the opposite. AXS shifting removes the hassle of routing cables and housing through the frame, and you'll never have to worry about cable stretch or wear. This means crisp, responsive, consistent shifting that rarely needs any adjustments. You'll also enjoy a cleaner cockpit thanks to one less cable, and you can customize the buttons on the shifter to do exactly what you want. Setup is as simple as mounting the derailleur and setting limit screws, installing the shifter, and then powering on the system and pairing the two. If you're concerned about the durability of the Eagle XO1 AXS system, don't be. Compared to mechanical Eagle groupsets, the Eagle AXS derailleur has been contoured around the frame design a bit more. This translates to increased chain wrap, which improves both load distribution and durability, reducing wear and tear on your chain and cassette for better longevity of components. Dually, this new positioning offers a whole 10-millimeters of increased clearance over mechanical Eagle rear derailleurs, meaning your less likely to bash it on a rock or encroaching root. If you do smack your derailleur against something, there's a special Overload clutch that disengages the motor in the event of an impact, allowi...