The Apex Eagle rear derailleur quietly and quickly shifts across 12-speed Eagle cassettes, while 1x-specific chain retention technology keeps the chain where it needs to beX-Horizon straight parallelogram design limits all movement to the horizontal axis, which makes ghost shifting impossible while also reducing shift forceCage Lock technology makes for fast wheel changes or chain installationRoller Bearing Clutch controls chain tension for consistent shiftingWorks with 12-speed mechanical Apex and Eagle shiftersCompatible with 50T and 52T Eagle cassettesUse with Eagle chainApex Eagle12sp52TLong1to1BLKUPC/EAN/GTIN: 710845887529