Fox Racing Shox
Fox Racing Shox 34 Float NA 2 Air Volume Spacer - 10cc
Changing volume spacers in the 34 FLOAT fork is an easy internal adjustment that allows you to change the amount of mid stroke and bottom out resistance. If you have set your sag correctly and are using full travel (bottoming out) too easily, then you could install one or more spacers to increase bottom out resistance.
Make sure to check Fox's specifications regarding the maximum number of volume spacers allowed in each fork model. If you have any doubt whether or not you can properly service your FOX product, then DO NOT attempt it.