SRAM PG1231 11-44 12s CP APEX XPLR SPLINEDMaximum range, minimum fuss This 12 speed 11 44T cassette provides 2x range in a 1x package and fits on a traditional 11 speed driver body for broad integration Smooth cog progression keeps jumps between cogs tightest when its time to go fast, with more meaningful gaps for climbing Compatible with FlatTop chains and 11 speed, Shimano style, splined road driver bodies Intended for use with XPLR 1x rear derailleurs