DESIGN & DETAILS: The Core Stability Disk is an excellent 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 your core muscles, increase balance and stability Difficulty may be increased by adding air or decreased by releasing air Comes with a training manual to optimize your knowledge of the product and exercises INCLUDES: One Core Stability Disk Training Manual Inflation Needle - pump for inflation not included