Made of neoprene rubber. Used for Buchner and fritted-glass funnels, porcelain filters without headpieces, and reverse flow cleaning of filter crucibles. Useful in filtration assemblies for supporting funnels, Gooch crucibles, and filter tubes. Adapter does not need to be fitted closely around the funnel stem to be functional. Autoclavable. Fits ours 1000ml and 2000 ml filtering flasks.