Always a bestseller, Pyrex® items are manufactured from thermal & chemical resistant Pyrex® borosilicate glass. Heavy walled Pyrex® Büchner filter flasks are ideal for vacuum filtration applications. The flask has a side-arm feature which consists of a short glass integral side-arm to accept 9mm bore vacuum tubing (B8A89801 - not included). With tooled neck to accept a drilled rubber stopper. Ungradua