Vacuum Desiccators Transparent are made of polycarbonate. These autoclavable vacuum desiccators can hold a vacuum up to 740 mm of Hg for 24 hrs without any greasing. The top dome and bottom base, molded in rigid and transparent polycarbonate, gives a crystal clear view of the desiccant placed inside. The knurled knob on the top provides easy handling of the dome. An internal groove is provided on the flange to hold a silicon rubber O-Ring. The polycarbonate desiccator is fitted with a self-lubricating PTFE plug. This plug works three-way i.e. vacuum creation, shutting off & vacuum releasing.