Calibrated to contain. Manufactured from borosilicate glass 3.3.

Designed from ASTM Specification E288, Class A unserialized requirements.

Flasks feature a mixing bulb in the neck, between the stopper and capacity ring, that contains approximately one-tenth of the capacity of the body to aid in dissolving or mixing the contents. With marking spot, [ST] ground glass stopper, and graduation ring blasted on the neck.