Wide range of uses: The breathing exercise tool includes 2 foam balls, small in size and lightweight, suitable for home, school and outdoor games. Lung Capacity Trainer: The Bubble Ball breathing trainer can increase lung capacity by exercising breathing muscles and increasing breathing endurance. Entertaining and entertaining: let children understand that moving gas can maintain the balance of light objects, understand the charm of physics, and cultivate children's interest. Bright colors: the lung capacity trainer is made of water-based paint colors safe and environmentally friendly, and other parts are made of wood and not painted. Safe to use: the blowing ball lung exerciser adopts 360 smooth polishing, no burrs, no won't scratch your hands, it's safe for you.