Specification Brand : Matala ExternallyAssignedProductIdentifier1 : 696447511379 ExternallyAssignedProductIdentifier2 : 0696447511379 ItemName : Matala 99981 Membrane Air Disc 9'' BHB-MD-225 ItemShape : Round ItemTypeKeyword : pond-filtration-equipment Material : Sand ProductDescription : The air diffuser platform allows you to mount the air diffusers firmly to the bottom of the pond and keeps the air diffusers out of mud. The air diffuser platform has a hollow base that can be filled with sand or gravel. Choose the number of disc diffusers your installation needs. Precision I-shaped perforated slots open when airflow is present and close when airflow stops, increasing durability and longevity, as well as cleanliness. These diffusers offer the lowest backpressure on the market, adding less than 6 inches of water depth backpressure, allowing you to use your air pump more efficiently. All models come with a single 3/4-inch PT female threaded outlet connection. UnspscCode : 56101600