[Features] Increase the oxygen content of the water. The amount of oxygen is large, the air diffuser stone is great for adding oxygen and reducing the CO2 content in hydroponics, circulatory systems, ponds, aquariums and aquariums. Keeps the fish healthy and active. The air stone was burned with high temperature, good air permeability, it is safe, washable and durable, non-toxic material keeps the fish healthy and active. Durable material. The aquarium air stone disc is made of sturdy and durable sand stone and stainless steel material, can be cleaned repeatedly over a longer period of time. Unique design. The bottom is a flat bottom and the top is a semi-ellipse. This construction in combination with the weight of the air stone allows the air stone to carry oxygen to the ground stably and promote air circulation on the ground. Easy to use. Suitable for 4mm or 8mm air tubes. Simply attach the air hose to the air inlet and place it wherever you want. [product information] product name:Fish tank bubble stone color:black Material:sandstone size:100*100mm Packing list (you can get after purchasing one item): Fish tank bubble stone*1 Please understand: 1. Due to the long shipping time, the item may be damaged during the shipping process, if the item is damaged, please leave us a message through the official website immediately before posting comments, and I will solve the problem for you. 2. Due to manual measurement, the size may have an error of 1-3cm. 3. Colors may vary from monitor to monitor.