A Buchner funnel is used for vacuum filtration. This two-part polypropylene funnel is 90 mm in diameter and has a capacity of about 300 ml. The filter has hundreds of small perforations for better filtration efficiency. The stem tapers from about 13 mm OD at the end to 18 mm OD at the cone - much smaller than typical porcelain Buchner funnels. Polypropylene is lightweight, acid and alkali resistant, easy to clean, and autoclavable. The top portion snaps to the lower one, forming a vacuum-tight seal that does not have to be greased.