Sibata* 2351A-Series Graduated Cylinders meet ASTM E-1272 Class A, Style I Specifications & USP Standards for Volumetric Glassware. Feature hexagonal bases for added stability. All cylinders, with the exception of the 2000 ml size, feature protective, polyethylene, hexagonal bumper guards. All markings are in durable, white enamel. Calibrated "To Contain."