Gaia essentials balance ball & Base kit features a 65cm balance ball that works great behind a desk in the office as well as at home as a yoga or stability workout ball. The base keeps the ball chair in place and it will not roll when not in use (balance ball and base are not connected and can be removed for ball only workouts). multi-purpose birthing ball is constructed of a quality rubber that is anti-burst and safe for users up to 300lbs. Kit includes an air pump, so you can setup and use directly out of the box. Note: it may be necessary to re-inflate the ball after initial inflation to allow the balls material to stretch to its final Size. Inflate ball with air, let stand for 24 hours, deflate 50% then fill again to 65cm height.