KIMAX® Volumetric Flasks with PE Stoppers have a graduation ring blasted on the neck and are calibrated to contain. The enlarged top of the stopper will protect the neck if the flask is tipped over. Supplied with a polyethylene stopper to fit in the ground neck. Marking spot on sizes 10 mL and larger. The 1 and 2 mL sizes are test tube shaped. All other sizes are of a conventional flask shape.