FOX FOX Float X2 Volume Spacer kit, 3 Pairs: Clip-in, Plastic, 0.25"

Air volume spacers are a fast and easy way of tuning your suspension. Changing the quantity of Air Volume Spacers changes the air spring curves to be more(adding spacers) or less(removing spacers) progressive through the mid-stroke and bottom-out resistance

If your sag is set properly on your bike but you're either using too much travel volume spacers are a great way to customize the performance of your bike.