The TRNR Gym Ball Pro 65cm is a must-have training tool, delivering greater core strength, balance, coordination, range of motion, joint stability, and postural alignment. By adding instability to your workouts, your deep abdominals, back and pelvic floor muscles have to work harder to keep you in position. This makes it ideal to strengthen these often-neglected muscles, preventing muscle imbalances, back pain, and injuries. Though specifically designed for core strength, the Gym Ball can be also used in a wide range of exercises targeting your arms, hips, glutes, and legs. It comes complete with a manual pump and TRNR innovative dual tool, allowing you to inflate the ball to its correct size (by lining up the two holes with the markings on your ball), as well as to remove the plug (using the forked end).