Made of high quality, heavy duty Borosilicate glass 150ml capacity. Narrow neck, flat bottom, beaded rim. 5.25" tall, 2.75" bottom diameter 2" neck length, 0.8" neck diameter Perfect for any science or home laboratory 150ml capacity Florence boiling flask made of high quality, heavy duty borosilicate glass. Narrow neck, beaded rim and flat bottom. No stopper included. Flask measures 5.25" tall. Eisco Labs Borosilicate glass has the following heat tolerances: Strain Point -515°C | Annealing Point 565°C | Softening Point 820°C.