USED - Karter Scientific glass flasks are versatile, used for holding and measuring liquid samples where a high degree is not necessary, also suited to mix, heat and boil solutions. Borosilicate glass 3.3 material, with spout for clean pouring. Enamel graduations and labeling field, high durale, and easy to read and mark. Uniform wall thickness distribution suited to heat. Compliance with ISO 1773 Laboratory glassware Narrow-necked boiling flasks.