This is a replacement ceramic disc for the Dymax Stainless Steel Diffuser with a diameter of 36mm. This 36mm diameter ceramic disc that has been specially refined to produce ultra-fine bubbles.These tiny bubbles have a much higher surface area to volume ratio than larger bubbles, which makes it easier for the CO2 to dissolve into the water.This ensures that your plants are getting the CO2 they need to thrive. Ultra fine and high dissolution rate to diffuse carbon dioxide into the aquarium. The ceramic disc is easy to install and can be replaced quickly and easily if it becomes damaged or worn. Fits:Dymax Stainless Steel Co2 Diffuser 36mm Diameter 25cm Length30cm Length40cm Length&Dymax Stainless Steel Co2 Diffuser 36mm Diameter – 8cm Length