Made of high quality, heavy duty, 3.3 borosilicate glass. Class A tolerance Amber color for light sensitive compounds 5ml capacity, single white graduation mark Fitted with 10/19 polypropylene stopper Stands 2.9" tall, and is 0.9" in diameter at its widest point 5ml capacity volumetric flask made of high quality, heavy duty 3.3 borosilicate glass. Amber color for light sensitive compounds. Single, white graduation mark. Class A, tolerance ±0.025 ml. Fitted with 10/19 polypropylene stopper. Flask stands 2.9" tall, and has a bottom diameter of 0.9". Eisco Labs Borosilicate glass has the following heat tolerances: Strain Point -515°C | Annealing Point 565°C | Softening Point 820°C