Eagle range on a drop bar bike? Now thats a party. The Apex Eagle rear derailleur quietly and quickly shifts across our 12-speed Eagle cassettes, while 1x-specific chain retention technology keeps the chain where it needs to be. Its the best of our road and mountain bike innovations in one package.Compatible with 50T and 52T Eagle cassettesWorks with 12-speed mechanical Apex and Eagle shiftersUse with Eagle chainRoller Bearing Clutch controls chain tension for consistent shiftingX-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 installation