Materials are strictly selected, free of phthalate and lead etc harm contents to human. It is healthier and safer in your daily exercise Premium solid integrally cast iron inside with soft touch neoprene coated, no smell Textured surface makes it is easy and comfortable to grip, don't slip out when sweaty It has a bit flat to stop rolling away on the floor, easy storage The soft neoprene surface is superfine processing, easy to clean. Never fade or crack in your daily exercise