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 - ColorGrey - Material: Mineral - Size: Approx. 4 x 2cm. - 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 live at ease. - Can be easily driven pumps, suitable for aquarium, fish tank and hydroponics. - Warm Tip: Dear buyer, due to lighting effect, monitor’s brightness, manual measurement, etc., there could be some slight differences in the color and size between the photo and the actual item. Sincerely hope that you can understand! Thank you! Package list: 20