Cartridges fully replace the functional mechanism of KS dropper posts. Pick the model and length of drop for the post you need to service. These are also called "Oil Pressure Sticks" and "Air Pressure Sticks" In KS Service Documentation.Not compatible with 27.2Fully replace the functional mechanism of KS dropper postsMay not work with OEM dropper posts KS Cartridges Dropper Seatpost Part EAN: 4718287314210