From the brand

The yoga half ball targets the core muscles of your body helping you to not only gain strength, trim and tone, but to strengthen the entire body and improve balance.
The Balance exercise delivers an ever-changing dynamic surface that you can stand on, jump on, kneel on, and lay on, to perform exercises to train and challenge every part of your body.
The core balance fitness helps to increase body strength and improve balance, coordination and body awareness which means overall improved fitness and fewer injuries.