Features: Do you want an tool to add oxygen to your hydroponic growing system? The air stone, whose purpose is to gradually diffuse air into the tank, providing oxygen for fish to breathe. Aquarium air stones moderate in size and outputs a large steady stream of tiny bubbles, no leaks, add enough oxygen to your fish, and also make your fish tank more beautiful. Air stones extend the life of your nutrient solution, help keep roots healthy, and promote exceptional growth. This stone is a must have for your aquariums. Feature - Color: Blue- Material: Mineral Stone.- Size: 4.00X1.50X1.50cm;/1.57X0.59X0.59in;- Made of mineral material, it effectively create water currents and dazzling underwater scenes.- Creates bubbles in fish tank while attached to an air pump.- Add oxygen to keep water roots healthy, put fishes live at ease.- Can be easily driven by Air pumps, suitable for aquarium, fish tank and hydroponics.- Good choice for your fish tank.Packing list: 20 x pumps