uxcell Cylindrical Shaped Fish Bowl Aquarium Air Bubble Creator Mineral Stone 5 Pcs Color: Blue; Package Content: 10 x Air Stone; Material: Plastic, Mineral; Model: NAR-021 Total Size: 0. 8"/ 20mm Dia; Net Weight: 150g; Connector Size: 0. 16"/ 4mm 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.