Gymnic Classic Plus Burst-Resistant Exercise Ball, Blue (65 cm) Incorporating balance-centric exercises into your workout enables your muscles to work harder to stabilize your body Multi-functional piece of equipment that can be used for both fitness activities as well as physical therapy practices Allows for a wide range of exercises to improve balance, coordination, flexibility and stabilization; Activate more muscles with each move and burn more calories Phthalate and BPA free; Made from burst-resistant, latex-free, vinyl which supports a maximum weight of 270 lbs. Available in 3 sizes: 55 cm (recommended for users 5' 1" to 5' 7"), 65 cm (recommended for users 5' 8" to 6' 2"), 75 cm (recommended for users 6' 3" and taller)