Durable and stable: made of natural cork, strong and firm muscle ball is very suitable as massage ball, treatment ball, relieve tension, pressure, pain and promote blood circulation. Because Cork is denser, it provides more support than foam balls. Ergonomic and lightweight: non-slip surface, hypoallergenic, anti-sweat, soft exterior, our portable cork yoga ball is a high-quality yoga necessities, not easily peeled off or broken.