Jillian Michaels 65 cm Anti-Burst Stayball Anti-burst exercise ball measuring 65cm in diameter Strengthens core, tones muscles, and improves balance Tough latex-free construction supports intense workouts Textured surface increases stability; 250-pound capacity For people between 5' 5" and 5' 11"; includes exercise chart and pump Textured Surface Anti-Burst Exercise Chart Included For Heights 5'5"-5'11"