Parr Model 3911 Hydrogenation unit for working volumes of 1ml to 200ml . Ace-thred vessels replace rubber stoppered vessels and eliminate cross-over contamination caused by leeching or sample retension. Complete unit includes all adapters needed for the supplied 8648 series bottles (1-4ml,3-8ml,8-20ml,10-35ml,25-75ml and 50-200ml). Units without vessels and adapters are available in explosion proof and air driven models.