SRAM REAR APEX EAGLE D1 12s 52T MAX BLACKThe 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 be X Horizon straight parallelogram design limits all movement to the horizontal axis, which makes ghost shifting impossible while also reducing shift force Cage Lock technology makes for fast wheel changes or chain installation Roller Bearing Clutch controls chain tension for