Made of high quality, heavy duty, Borosilicate 3.3 glass 5ml capacity, single white graduation mark Class A tolerance. Compliant with ASTM-E288 standards Fitted with blue snap cap Stands 3" tall, and is 0.85" in diameter at its widest point. Neck diameter measures 13mm 5ml capacity volumetric flask made of high quality, heavy duty Borosilicate 3.3 glass. Single, white graduation mark and a blue snap cap. Class A, tolerance, ±0.020ml. Calibrated to contain. Flask stands 3" tall, and has a bottom diameter of 0.85". Neck has an outer diameter of 11mm and an inner diameter of 8mm. 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.