Environmentally friendly material,made of green rubber ,harmless to human. Light weight, durable, easy to carry. Suitable for home or outdoor use Ageing resistant, wear resistant. This grip ring is shaped gear and it is not easy to slip.It is easy to be carried and suitable for office workers, the elderly, children. It can develop hand strength, increase finger dexterity, promote blood circulation, besides, deflate tension when working under stressful