The Whirly Board Stabilizer Ring was specially designed and created to accompany our Whirly Board. It is an excellent addition for people new to balance boards, used with fitness exercises, helps stabilize you at a standing desk, and can be used under a desk with your board as an under desk footrest. The ring is a semi-rigid rubber with a hardness of about 90A, can be very slightly deformed with pressure, but always holds its shape. The combination of hardness and texture provides just the right amount of traction between the ring and the center ball to offer support without hindering motion. The ring supports standing desk users who want to have complete focus and stabilization as well as people who want to sit down for a while, continuing to move their legs and feet. The ring provides a receptacle for the center ball that keeps the board's location stationary but still allows motion in all directions. The ring also acts as a sort of “training wheel” for new users getting used to the feel of a Whirly Board. Balancing will still feel like a challenge, but the ring offers subtle assistance, helping you maintain your balance for longer periods of time. The ring also helps hold the board in place for fitness moves like push-ups or mountain climbers. While the ring helps the board maintain its location, it does not hinder general movement. Enjoy the core-strengthening challenge of maintaining balance without the frustration of the board sliding away.