Come and Check Our Promo Solutions.This wrist ball is made of zinc alloy + polycarbonate + silica gel. It is a pure mechanical wrist ball. It can be lit without a battery or power supply. It is harmless to the environment and can exercise and play with the toy without electromagnetic radiation. Strengthen arms and wrists, strengthen muscles and bones for exercise. The logo can be customized above. Pls check inventory and detailed info with us before placing your orders.