Balance GoFit - 13" Core Disk with Inflation Needle - Red GF-CDISK37.99Buy!$BestBuy.comDelivery: in USA ReportThe GoFit 13 In. Core Balance Disk with Training Manual is an ideal way to add a new level of difficulty to your workout. The soft disk can be utilized in pilates, yoga, or regular workouts to work yo more→ur core muscles, and increase balance and stability. Difficulty may be increased by adding air or decreased by releasing air. It comes with a training manual to optimize your knowledge of the product and exercises. * Before beginning any weight loss or exercise program, you should consult with your physician.