The Kumo Balance Disc is a 14" diameter inflatable cushion that works great as a fulcrum for the Kumo Board. By itself it works great as a balance and fitness trainer for standing or sitting. Inflation level adjusts via mouth inflation and only takes a few breaths to inflate to a good level for general use. Inflate less for an easier experience, inflate more for a more challenging experience. Also works great as a "wiggle seat" for children who have a hard time staying still while seated.