These 3 o-rings can be used to replace the RockShox Charger 2/2.1 compression assembly seals for the high and low speed compression adjusters. The thickest of the 3 o-rings is to replace the stock u-cup seal that often causes a slow leak from the compression adjuster (and fix it for good). The two thinner seals are for the low speed compression adjuster. Depending on the model year, one or the other will be needed.