500mL separating funnel for use in titrations Made from high-quality, lab-grade borosilicate glass Funnel comes with an interchangeable plastic stopper (socket size 24/29) Key stopcock made from borosilicate glass Can be used for titration or neutralization procedures This 500mL separating funnel is made from high-quality, lab-grade borosilicate glass. The funnel comes with a borosilicate glass key stopcock and interchangeable plastic stopper. The socket size of the funnel is 24/29. A must-have in chemistry classrooms and laboratories performing titrations and neutralizations. Eisco Labs Borosilicate glass has the following heat tolerances: Strain Point -515°C | Annealing Point 565°C | Softening Point 820°C.