Flask Conical 1000ml, narrow neck, borosilicate glass-EIS-CH0424H offers a thoughtfully designed, durable resource for hands-on learning. High Quality Borosilicate glass 1000ml with 200ml graduations (1) Single Flask Narrow Neck Glass Erlenmeyer Narrow Neck Flask 1000ml, borosilicate ( Single flask ). Flask measures 8.5" tall and has a base diameter of 5". Inner neck diameter measures 35mm, and outer diameter measures 42mm. Autoclavable, with superior chemical durability. Low temperature gradient- can withstand high temperatures & thermal shocks. Eisco Labs Borosilicate glass has the following heat tolerances: Strain Point -515°C | Annealing Point 565°C | Softening Point 820°C. Eisco Labs proudly manufactures its own products using state-of-the-art equipment, and following the highest standards of quality control. Each product is carefully designed by a team of laboratory professionals and experienced engineers with quality and durability in mind. They are manufactured with only the highest grade, raw materials and according to international quality standards to ensure that they can withstand use in even the toughest laboratory environments.