KIMAX flask with a graduation ring blasted on the neck. Calibrated to contain. With a marking spot ground glass stopper is supplied. Mixing bulb in the neck, between the stopper and capacity ring, contains Approximately one tenth of the capacity of the body to aid in dissolving or mixing the contents of the flask. Designed from ASTM Specification E288, Class A unserialized requirements. Replacement stopper is 41900R.