High vacuum Stopcock that eliminates exposure to corrosive materials. Use to at least 13.6 kg internal pressure. Variable openings from 0-3mm to 0-10mm. Ultimate vacuum of 10-7 can be realized with standard three seals. Smooth acting Valve permits fine adjustment of opening. Front ring seal makes a positive closure against a precision-formed heavy glass Seat. PTFE plug is not bake able. O-rings are not replaceable. Reference marks on body aid in repetitive setting. Available with arms at 90 Degrees or high vacuum three-way.