The diffusion plate decomposes the CO2 into tiny streams of bubbles, then the CO2 can easily dissolve in the water thus allowing the plants to absorb the CO2 for photosynthesis The steel diffuser stainless steel is strong and durable, not easy to break, and non-toxic to your pets and plants Ceramic disc is replaceable, easy to remove and replace, and please tighten when you install it Suitable for aquariums up to 18mm wall thickness Total length of J-Pipe is 25cm. The ceramic disc is 36mm in diameter, the CO2 diffuser is suitable for standard 4*6mm CO2 air tubes (inner diameter 4mm and outer diameter 6mm)