Natural Fitness Pro Burst Resistant Exercise Ball Use Natural Fitness Burst Resistant Exercise Balls for fitness, core stability, yoga, Pilates and balance exercises. Improves back and core strength while sitting at home or office. Includes: Exercise Instruction Chart (1) Fast Pump (2) Inflation Plugs (1) Plug Remover Three (3) sizes/diameters vary with color for user height: 55cm- Small (Plum); 65cm- --Medium (Olive); 75cm- Large (Slate) Proprietary burst resistant (up to 300lbs) composite for safety; Designed to deflate slowly if punctured Phthalate-free (6P)/Toxic Free, latex-free material to be skin-friendly