Kimax® flask with a graduation ring blasted on the neck. Calibrated to contain. With a marking spot on sizes 10mL and larger. Supplied with a Cat.No. 6-28160R polyethylene stopper to fit in the ST ground neck. Enlarged top of the stopper will protect the neck if the flask is tipped over. The 1 and 2L sizes are test tube shaped. All other sizes are of a convenient flask shape.