Description An airstone, whose purpose is to gradually diffuse air into the tank and provide oxygen for fish to breathe, is an necessity to have around your house if your are a lover of aquatic animals. Our air stones are made of mineral material. Feature - Color: Blue- Material: Sand.- Size: 4.7x2x2mm. - With high temperature sintering, the stones are sturdy and durable, have high dissolved oxygen rate and create even and tiny bubbles rather than a limited number of large ones.- An airstone, whose purpose is to gradually diffuse air into the tank and provide oxygen for fish to breathe, is an necessity to have around your house if your are a lover of aquatic animals.- Our air stones are made of mineral material.- Comes with 10 Pcs Ball style air stones.Packing list: 10 x Air stone