This plug works three way i.e. Vaccum Creation, Shutting off & Vaccum Releasing. The Polypropylene stopcock is fitted with a self lubricating PTFE plug. Desiccators are made of Polypropylene and Polycarbonate Autoclavable vaccum desiccators can hold vaccum upto 740 mm of Hg for 24 hrs. Without any greasing the top moulded 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 lower part is made of Polypropylene. An internal groove is provided on the flange to hold a silicon rubber O Ring.