These PYREX® gas dispersion tubes have a 30mm diameter coarse porosity (40 to 60µm) fritted disc and are used to disperse or scrub gas in liquids. The size of gas bubbles depends upon the porosity of the fritted disc and the liquid used. The finer porosity discs give smaller bubbles, however greater gas pressure is required. Centrally located stem permits insertion through small openings. For more information on fritted products, please check the Guide to Selecting and Using Fritted Glassware under Technical Literature.