Made of high quality, heavy duty Borosilicate glass 25ml capacity. Narrow neck, round bottom, beaded rim. 3.5" tall, 1.75" bottom diameter 2" neck length, 0.6" neck diameter Perfect for any science or home laboratory 25ml capacity boiling flask made out of high quality, heavy duty borosilicate glass. Narrow neck, beaded rim and rounded bottom. No stopper included. Flask measures 3.5" tall. 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.