Squibb Separatory Funnel, made from quality borosilicate glass 50 ml capacity, ungraduated. PTFE Stopcock Interchangeable Plastic Stopper, Socket Size 14/23 8" long, 2.25" wide 50ml capacity Pear Shaped Separating Funnel, made of high quality borosilicate glass. Funnel has a 14/23 size socket and includes an interchangeable plastic stopper. PTFE key stopcock. Ungraduated. This funnel measures approximately 8" long, and 2.25" wide. Neck diameter measures approximate 0.6". Eisco Labs Borosilicate glass has the following heat tolerances: Strain Point -515°C | Annealing Point 565°C | Softening Point 820°C.