This sophisticated Ultimate Balance Ball Chair from Gaiam gives you great comfort and ergonomic back support while easily blending in to any contemporary office or home setting. The patent-pending design lets you engage your core, align your spine, and even increase your energy, all while you sit. The easy-glide five-wheeled base provides a sturdy and stable foundation while offering added mobility in the office or home and the durable nylon and steel fabrication makes it built to last. You can easily remove the anti-burst 52-centimeter ball for exercising and stretching too. Includes a downloadable exercise guide and instructions. Some assembly is required.