These flasks are calibrated to contain and feature a graduation ring blasted on the neck

Sizes 10mL and larger feature a marking area. Supplied with a [ST] PTFE stopper with color-coded handle. The 2mL size is shaped like a test tube; all other sizes are of a conventional flask shape. Sizes 5mL and larger are designed from ASTM Specification E288, Class A unserialized requirements.