The DT Swiss Ratchet End Caps allow conversion of existing DT Swiss hubs between different wheel spacing standards, or can serve as a replacement for missing or lost end caps. Specific compatibility is described below for the various options in the drop-down menu. The 12 x 100mm option is compatible with 240S CenterLock "fifteen" front hubs, 240S CenterLock straight-pull front hubs, model-year 2014 15 x 100mm white 180 front hubs, and 2016 RC Spline black hubs. The 15 x 100mm option is compatible with model-year 2011 and newer 240 CenterLock disc hubs with 18mm outer diameter axle. It does work for 15 x 110mm Boost, as well. The 12 x 142/148/157mm Shimano/SRAM option works with DT Swiss 180, 240, and 440 mountain hubs with 12 x 142mm, 12 x 148mm, and 12 x 157mm hub spacing. The same end caps are used for all three hub spacings and Shimano HyperGlide freehubs. They do NOT convert non-Boost hubs to Boost spacing. The 12 x 135mm option works with model-year 2011 and newer 240, 350, and 440 hubs. It converts these hubs from standard Quick-Release to 12 x 135mm thru-axle. This option also serves to convert 150mm Quick-Release hubs to 12 x 150mm thru-axle. The 12 x 142mm Road option works with DT Swiss 180, 240, and 350 Road hubs with 11-speed freehub bodies/cassettes. They are compatible with classic flanged hubs only, not straight-pull hubs. The SRAM XD option fits DT Swiss hubs with 12 x 142mm, 12 x 148mm, 12 x 177mm, and 12 x 197mm hub spacing, as all these axle spacings use the same end caps. It only works with SRAM XD freehub drivers.