Exercise balls are one of today's top fitness tools - and for good reason! Using an exercise ball will improve the strength of the abs and the lower back. Since the exercise ball is unstable you have to constantly adjust your balance, which in turn will improve your balance, proprioception and flexibility. As an extra challenge you can use the exercise ball as a bench using free-weights to target those hard to reach stabilizer muscles. This ball is specially designed to offer firm support for more controlled exercise routines. Theragear exercise balls are made with a special material that prevents the ball from dangerously exploding if accidentally punctured. If punctured the air is released gradually so Secure Max System balls deflate slowly - and safely.