These KIMAX volumetric flasks are permanently marked with an individual serial number. Supplied with a Certificate of Graduation Accuracy. Graduation ring blasted on the neck. Calibrated to contain. With a marking spot. Standard Taper ground glass stopper is supplied with the flask. Cylindrical bodies allow for better mixing and drainage, and for ease in withdrawal of samples by pipet. Wide base (circular for sizes 1, 2, and 5 mL and hexagonal for sizes 10 and 25 mL) imparts much greater stability than is possible with a conventional shaped flask.