From NAUDH This Naudh 02 inch porcelain Buchner funnel with fixed perforated plate. Glazed inside and out except for rim. Naudh porcelain & ceramic labware has excellent thermal-shock resistance Capacity With straight sides above the perforated plate. laboratory filter funnel used under reduced pressure. It consists of a shallow porcelain cylinder with a flat perforated base. A Buchner funnel is a piece of laboratory equipment used in filtration. It is traditionally made of porcelain, but glass and plastic funnels are also available. On top of the funnel-shaped part there is a cylinder with a fritted porcelain disc/perforated plate separating it from the funnel.