Eisco Labs Glass Erlenmeyer Flask High Quality Borosilicate glass Wide Neck Flask (1) Single Flask 1000ml Capacity with 200ml graduations Eisco Labs Glass Erlenmeyer (Conical) Wide Neck Flask 1000ml, Borosilicate ( Single flask ) with 200ml graduations. Made with High Quality Borosilicate glass. Stopper size no.10 Eisco Labs Borosilicate glass has the following heat tolerances: Strain Point -515°C | Annealing Point 565°C | Softening Point 820°C.