Used as an air splitter for air compresssors. The air stone ensure effective distribution of water for effective breaking of surface tension.

To use, fasten the tip of the air ston to one end of the a hose anf the other end of the hose to an air compressor or aerator. 

You know during hatchery and in general fish need air. And air comes from aerators and also from atmosphere. Both air are important. The air stone helps the compressor break down the density of water to almost vapor like so it provides oxygen and also breakes the surface of the water which normally will be still, there by making space inside the water so that atmospheric air can find way in. 

Its also good to position the hose or air stone somewhere or somehow that it can bubble to the surface of the water. As the case may be.

Size of each: 1.4 inches diameter by 1.5 inches height