Our Medium Mini Stability Ball™ will have a big impact on your workout and posture. Use it during your workouts to create instability in your stabilizer muscles to sculpt a lean and toned body. You can also use it after a long day of sitting for targeted self-massage, stretching and stimulating your connective tissue, ligaments, blood vessels and fascia. Easily adjust the firmness and pressure of your ball by inflating or deflating the air inside.