Polyethylene funnels are one piece design with a fixed or removable porous filter plate supported by a multiple ring grid. Filter plates are made of high density polyethylene 6.4mm (1/4") thick with a non-porous ring at the periphery of the plate which seals filter paper when used. Vacuum connector accepts 12.7mm (1/2") I.D. tube. Available in two porosities (medium and coarse). Special sizes and features made to order. Use below 52°C (125°F). With Perforated Filter Plate Section. Similarly, these Buchner funnels are also available with a fixed or removable perforated filter plate. The plate is made of 4.8mm (3/16") thick high density polyethylene and has 4.8mm (3/16") perforations on 11mm (7/16") centers. The fixed version is for coarse filtration or use with a cloth or paper filter. A removable filter plate is available for use in precious metals recovery. Use below 52°C (125°F). 24" and 36" sizes come crated.