Flask Conical 100ml, wide neck, borosilicate glass-EIS-CH0426A offers a thoughtfully designed, durable resource for hands-on learning. High Quality Borosilicate glass (1) Single Flask Wide Neck Glass Erlenmeyer Wide Neck Flask 100ml, borosilicate ( Single flask ) Eisco Labs Borosilicate glass has the following heat tolerances: Strain Point -515°C. Annealing Point 565°C. Softening Point 820°C.