These 125mL heavy duty PYREX® distilling flasks are suitable for microchemical applications. The sidearm is located approximately 137mm from the bottom of the flask to meet the requirements of ASTM E-1405 and can be used in ASTM tests D-86, D-233 and D-447. Adaptable for use with thermometers calibrated for 76mm immersion. Flasks take a No. 2 rubber stopper.