Specification Brand : elephrun BulletPoint : exercise ball is good for health, solid and never get rusty Color : Black ItemName : 30mm - 60mm 304 Stainless Steel Solid Baoding Balls For Wrist Strengthening Relaxation (45mm 2pcs) ItemShape : Sphere ItemTypeKeyword : manual-massage-balls Manufacturer : Gosen Industry Corporation Limited Material : Stainless Steel ProductDescription : These balls are made from AISI304 stainless steel. They are solid and never get rusty in normal conditions, still new even last for 10 years!