SRAM REAR APEX XPLR D1 12s 44T MAX BLACKThe Apex XPLR derailleur hits the sweet spot of smooth jumps over a big gear range, all with unmatched chain security and the simplicity of a 1x drivetrain X Horizon straight parallelogram design limits all movement to the horizontal axis, which makes ghost shifting impossible while also reducing shift force Works with 12 speed mechanical Apex and Eagle shifters Clutch controls chain tension for consistent shifting Compatible with cassettes with 44T