PYREX® 500 mL Round Bottom Kjeldahl Flask with

These 500 mL PYREX® Kjeldahl flasks have tooled finished necks for extra strength and uniform rubber stopper (No. 6) fit. Wall thickness is controlled to offer the optimum balance between thermal shock and chemical resistance. They can be used in ASTM E-258 procedures. Care must be taken to ensure the bottoms of the flasks do not come in contact with the heating elements. Most Kjeldahl equipment manufacturers have ring supports for this purpose. Reference: ASTM E-1377.