uxcell Fish Tank Ball Shape Aquarium Bubble Air Stones Airstone 30mm 10 Pcs Blue Color: Blue; Air Stone Diameter: 30mm / 1.1"; Net Weight: 224g; Product Name: Aquarium Airstone Connector Diameter: 4mm/ 0.1"; Material: Mineral, Plastic; Model: NAR-021 Made of mineral material, it effectively create water currents and dazzling underwater scenes. Creates bubbles in fish tank while attached to an air pump(Not Included). An ideal tool to add oxygen to your hydroponic growing system.