Use 00.7518.137.000 12-SPEED BLACK;

The SRAM GX Eagle 12-Speed Rear Derailleur harmoniously shifts through all 12 gears of your Eagle drivetrain without noisy chain slap or annoying ghost shifts holding you back on the trail. Borrowing shifting technologies from its pricier XO1 sibling, the GX Eagle 12-Speed Rear Derailleur is a low-cost alternative that retains SRAM's X-Sync 14-tooth lower pulley system, X-Horizon parallelogram design, and Type 3 Roller Bearing Clutch. Best of all, it's fully compatible with Eagle XO1 and XX1 drivetrains, giving you an affordable replacement in case of a catastrophic crash. Instead of its forged aluminum cage and titanium spring found on the XO1, the GX 12-Speed Rear Derailleur employs a traditional aluminum cage with steel spring as a cost-conscious alternative without sacrificing durability, albeit with a minor weight penalty. Expanding on SRAM's signature technologies, the X-Sync 14-tooth lower pulley accommodates the larger 10 to 50-tooth cassette found on Eagle. For silent operation, the Type-3 Roller Bearing Clutch eliminates derailleur bounce and chain slap when you're rallying over punishing trails. Also, it packs SRAM's X-Horizon design, which limits horizontal derailleur movement that contributes to ghost shifting, as well as X-Actuation for precise shifts of your 1x drivetrain.