VIV's hand-blown Glasswares are the most favored in the aquatic world offering an outstanding elegance to any aquarium. Designed with an emphasis on functional beauty, each VIV glass piece is handmade in China by skilled glass workers. The pieces are formed from crystal clear borosilicate glass, the same material used to make high end lab equipment. Japanese glass craftsmen carefully hand finish each VIV part to the highest standards with smooth edges and attention to the smallest details. VIV's Tall CO2 Bubble Counter and Diffuser is designed for aquariums up to 15 gallons. This product simply combines the two functions into one unit. It is designed to mount inside the aquarium with a suction cup. The diameter of the ceramic disc is 18mm. Height: 100mm Important Info: All ceramic discs, tubes, or surfaces MUST be soaked in water for at least 30 minutes before use. Always wet the glass tubing before inserting the silicon or rubber tubing to avoid damaging Glassware.