Pyrex 6" (25x150mm) Borosilicate Glass Test Tube 55ml Boiling Tube with RimProduct Description These high quality borosilicate glass test tubes feature a round base and rimmed tops, making them easy to handle and ideal for lab use. Made from borosilicate glass 3. 3, they offer excellent resistance to heat and chemicals. The tubes have consistent wall thickness and precise dimensions to ensure reliability and durability in experiments. Each test tube holds 55 ml and measures 25 mm in diameter by 150 mm in length.