The 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. Quietly and quickly shift across Sram's 12-speed cassettes with 44T large cogs knowing you’ll have the gears you need.   Features Compatible with cassettes with 44T large cogs. Use with Flattop chain. Works with 12-speed mechanical Apex and Eagle shifters. Clutch controls chain tension for consistent shifting. X-HORIZON straight parallelogram design limits all movement to the horizontal axis, which makes ghost shifting impossible while also reducing shift force.   Specification Speed: 12s. Cable pull ratio: X-actuation. Max tooth: 44. Pulley bearings material: Steel. Cage material: Aluminium.