50mL Flask, Reaction, 14/20 Outer Joint, Valve, Airfree, Schlenk. Kjeldahl shape facilitates heating and stirring while permitting easy transfer of liquids or solids. Lower portion of flask fits standard heating mantles. Available with a choice of a 2mm high vacuum glass stopcock having a Stainless Steel constant pressure retaining device or a 0-4mm Chem-Cap Airfree inlet valve.