Borosil Amber Wide Mouth Class A Volumetric Flasks are individually calibrated by automatic, laser-controlled calibration equipment. Supplied with standard taper glass stoppers. Flasks comply with ASTM E-288, Class A. 20mL option is not covered in ASTM. 5mL, 10mL, and 20mL options have a trapezoidal shape for improved stability. Avail. from 5mL to 250mL. Amber protects from 300nm to 500nm. Larger Amber Class A Flasks Avail. in Product Family 5655. In collaboration with Borosil Glass Works, Foxx Life Sciences is proud to bring the outstanding quality of Borosil Type 3.3 Borosilicate glassware to North America for the first time. Manufactured from the same USP Type 1 borosilicate glass that North American scientists have come to trust, Borosil Laboratory Glassware offers unparalleled mechanical strength, clarity and reliability at competitive prices. And thanks to a unique annealing process, Borosil Glassware is stress-free and incredibly resistant to thermal shock.