Low vacuum, non-shedding PTFE stirrer bearing factory tested to below 3 Torr. Ace-Thred™ version. Rated for up to 400 rpm with both glass (polished rather than precision ground is best) and stainless steel shafts of 10 mm. Wetted materials are PTFE, Rulon™, PEEK and a perfluoroelastomer o-ring.