If you've found that you are pushing the 38 to it's limits or just want a little more progression out of the fork here is the factory option to help you with that! These are 10cc volume spacers to help decrease the amount of air volume in the fork increase progression of resistance throughout the travel.38 FLOAT Volume Spacer Configurations *Add 1 for Factory installed spacers on E-bike models. Fork Travel Volume Spacers Factory Installed Max VolumeSpacers 180mm 1 4 170mm 2 5 160mm 3 6 150mm 4 6 FOX Volume Spacers Air Springs & Parts UPC: 821973401508