BorosilÂ® brand Flasks are designed to deliver the best combination of thermal shock resistance along with physical strength and resistance to chemical attack. Borosilâs Narrow Mouth Conical Erlenmeyer Flasks comply with IS 1381(Part I), DIN/ ISO 1773 and are manufactured to withstand the demands of the modern laboratory. Uniform wall thickness distribution makes these flasks ideal for heating. The conical form makes these flasks also suitable for mixing liquids. The easy-to-read scale and large labeling field helps to ensure for easy marking. 25mL to 5L are graduated in a ceramic white color.