KIMAX flask with a single graduation ring blasted on the neck, calibrated to contain. A ground glass stopper is supplied with a marking spot on sizes 10 mL and larger. Sizes 5 mL and larger are designed from ASTM Specification E288, Class A unserialized requirements. The 1 and 2 mL sizes are test tube shaped and are calibrated to E237 tolerances. Replacement stopper is 41900R.