High density polyethylene Dewar Flask with vented and insulated HDPE covers. They are unbreakable, chemically resistant, and withstand temperatures from -196 to 100°C (-321 to 212°F). Double walls are filled with foamed urethane to minimize heat exchange. May be used for short term storage of dry ice-solvent, liquid nitrogen, or for use as a hot bath. They are ideal for storing frozen biological specimens. All available sizes feature molded-in-ribs for stability and a carrying handle on the 1, 2, and 4 liter sizes.