Flasks are permanently marked with an individual serial number and supplied with a Certificate of Graduation Accuracy

Flasks are calibrated to contain and supplied with a polyethylene snap cap and a marking spot. Graduation ring is blasted on the neck. Flasks meet requirements for accuracy, appearance, glass quality, calibration line, and inscriptions of former NBS Circular 602. The 500mL size is suitable for determination of specific gravity of fine aggregate (ASTM C128). Designed from ASTM Specification E288, Class A serialized requirements.