No longer is “anti-burst” reserved for PVC construction, as these balls safely deflate if punctured. Outer skin is eco-safe and free of Phthalate, latex, and other common fitness materials, removing skin reactions or allergies. Burst-resistant up to 500 lb; 2,200 lb static-load limit. Available individually or in packs with storage and instruction. Multi-Size 6-Ball Pack includes two 55 cm, three 65 cm, and one 75 cm; Multi-Size 12-Ball Pack doubles the quantities.