These Dewar containers are made of borosilicate glass 3.3 (DIN/ISO 3585). Extra tough design with blue plastic-coated cover made of galvanized iron or stainless steel. With thermally insulated plastic lid held by two springs. Detachable carry-handle. The lid has to have a 2 mm hole when the containers are used to transport and store liquid nitrogen or any other gassing refrigerants.