New design 2023 with bright blue ring around the air stones and full parts provided in the package for oxygen enrichment for aquarium fish tank. This airstones for aquariums has total four sizes 2inchs ,3inchs,4inchs,5inchs can be selected base on the different sizes of your fish tanks, with Stable material,this aquarium bubbler stone is suitable for both seawater and freshwater use ,help keeping fish healthy. The fish tank bubble airstone make by Nano aerolite with high-density pores, denser bubbles and higher oxygen content ,can work with low air pressure,but the deeper the bubble stone placed in the water, the greater power of air pump is needed to support. And air volume can be adjusted according to different situations by using the check valve. With high-density design , the aquarium airstone working with the noise 20dB only to make sure the fish Undisturbed. Easy to install, first connect the sand stone with a air pump , and after the air pump connected to the electric supplies , repeatedly plug and insert this fish tank air stone inlet pipe , so that the bubble stone can quickly backflow water. Before normal use,make sure soak the air stone for two hours in order to have the top efficiency.