【Specification】 Please pay attention to the correct size when buying. Black 13:13 cm, air stone suitable for 4mm tube with inner diameter; black 21:20 cm, suitable for 8mm trachea; white 13:13 cm, suitable for 4mm and 8mm trachea, white 20.7: 20 cm, suitable for 4mm and 8mm trachea. Durable: The bubble plate is manufactured at high temperatures and the fine bubbles can increase the oxygen content, reduce CO2 and increase the pH value. It can also be easily washed for reuse. < Br> High quality material: The disc uses finely compressed material, the bubble is small, and the bubble is concentrated on one surface. Br> Adjustable atmosphere plate: The size of the bubble can be adjusted. The smaller the gas volume, the smaller the bubble. Please soak in the aquarium for two hours before use, the effect is better. If the water depth exceeds 40 cm, the power of the air pump can be increased properly. Br> 【Application】 Aquarium air stone ideal for freshwater, salt water, hydroponics, aquatic
