Merrithew Air Balance Ball (10-Inch, Red) Use for strengthening, improving flexibility and muscle relief The Anti-Burst ball measures 25cm (10-inches) in diameter The nubbed surface of this massage ball stimulates the muscles while you work out Comes deflated. Needle-point pump included for easy inflation Can be used in place of the STOTT PILATES Mini Stability Ball to enjoy the added benefit of gentle massage. Can be used with all STOTT PILATES Mini Stability Ball DVD Programming Can be used in place of the STOTT PILATES Mini Stability Ball to enjoy the added benefit of gentle massage. Can be used with all STOTT PILATES Mini Stability Ball DVD Programming. The nubbed surface of this massage ball stimulates the muscles while you work out. It can be used for strengthening, improving flexibility and muscle relief. Anti-Burst Needle-point pump included for easy inflation of the anti-burst Air Balance Ball.