Featuring a 65cm (26 inch) diameter, the Onyx Black PTP CoreBall is recommended for individuals from 165cm (5 ft 4) up to 185cm (almost 6 ft 1). Back pain often stems from poor posture, muscle imbalances and weak core engagement. Add this essential piece of equipment to your home gym to build a strong core, foundation to any functional movements. Included are a range of exercises carefully designed for you to learn just how to do so. You can also improve your posture by simply using your PTP CoreBall as an alternative to your office chair. Features: • Made in Australia to world-leading standards: free from BPA, phthalates, latex and led • Over 50 exercises included, designed by Movement Therapist and Pilates Expert • Special anti-burst structure and weight rated up to 1000kg (2200 lb) • Convenient non-slip texture and pump included • Improves core stabilisation and balance • Dual purpose: piece of exercise equipment or sitting solution