Borosil® Amber Wide Mouth Class A Volumetric Flasks are individually calibrated by automatic, laser-controlled calibration equipment. Supplied w/ standard taper glass stoppers. Flasks comply w/ ASTM E-288, ClassA. 20mL, 500mL, 1L options is not covered in ASTM. 5mL, 10mL, & 20mL options have a trapezoidal shape for improved stability. Avail. from 5mL-1000mL. Amber protects from 300nm to 500nm. Larger Amber Class A Flasks Avail. in Product Family 5655. In collaboration w/ 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, & reliability at competitive prices. & thanks to a unique annealing process, Borosil® Glassware is stress-free & incredibly resistant to thermal shock.