Material: High quality and hard materials, long-term use, biosecurity. Suitable for the aquarium, aquarium and circulation system. Increase oxygen and reduce carbon dioxide content. Use: The ideal stone disc is suitable for freshwater stones, seawater aquariums, water cultivation or aquatic farms, aquatic crops, creating magnificent water sites, it is enough for Connect the aquarium air pump. Easy to use: Connect to the air pump and place it in water to help the air pump in the water. Repeated use: The air slabs can be used for a long time and you can easily clean it again. High temperature sintering, uniform air, great air Model: diameter of about 4 cm from Material: High temperature sinter sand Product: Other aquarium products Quantity: 4 Characteristics: The high temperature sintered stone consists of high temperature sintering, different from the general commercial bubbles. The material is firm and durable, and it can be cleaned several times, long-term use. Instructions for use: 1. Connect the air molds with an air tube. 2. Please soak this product in the water for 15 minutes before use. 3. Long-term use, such as the occlusion of dirt, the bubbles reduce, can be cleaned several times