With Resist-A-Ball, you"ll add challenge to your workout while improving posture, core strength, balance and flexibility * The Resist-A-Ball is burst resistant with raised ribs for improved grip and a recessed inflation point * Includes exercise wall chart, foot pump and measuring tape * 65 cm ball generally works best for users around 5 ft 8 in to 6 ft 1 in tall; user capacity: 800 lbs