This airstone will ensure its practicability in the work of high performance. It looks like a round disc with a air pump interface. With the delicate surface and even air outlet, it can be used to transport oxygen to the fishes and other living things not only in fish tank, but in pond and aquarium and other places. Feature - Color: White. - Material: Ceramics. - Size: Approx. 5x5x3.5cm - and hard material, good for long-term use and safe for living things. - Can be washed repeatedly. - Beautiful air bubbles add beautiful scenery to the aquarium and fish tank. - Great to add oxygen to your hydroponic growing system: Increase oxygen levels, lower CO2 and raise PH value. - Warm Tip: Dear buyer, Due to lighting effect,monitor's brightness,manual measurement and 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