Amazon.com: Enovi ProBalanceΩ Ball Chair, Yoga Ball Chair Exercise Ball Chair with Slipcover and Base for Home Office Desk, Birthing & Pregnancy, Stability Ball & Balance Ball Seat to Relieve Back Pain,
Exercise Balls for Office Chairs - Good or Bad - Work Saver Systems
Classic Balance Ball® Chair - Gaiam
What Are the Pros and Cons of Having an Exercise Ball for an Office Chair?