Inflatable exercise balls

• Use to improve balance, coordination, flexibility and strength, or just for fun
• Used by therapists as an aid for vestibular movement and equilibrium therapy,
  by fitness professionals as an aid for stretching and strength programs, as seats,
  and even by pregnant women in birthing classes
• Non-slip surface is ribbed for extra security
• Underinflate to give a soft, mushy feel or fully inflate for a firm, bouncy feel
• Supports up to 300 lb (136kg)​​​​​

Please find more information here