Anti-Splash Adapters With Fritted Disc, Modified provided by STE-Mart feature two 4mm return holes at bottom of the inner tube to allow the solution to reflux to evaporating flask. The upper joint is a standard tapered outer joint, while the lower joint is a standard tapered inner joint which extends up to the inside of the bottle. In the lower end of the outer joint, there is a disc whose diameter is 10-15μm, which is used for filtering coarse precipitate and gas washing.