SIBATA 2303A-Series Volumetric Flasks meet ASTM E-288 Class A Specifications & USP Standards for Volumetric Glassware. Feature machine-blown bodies and heavy-beaded, heavy-tubing necks, tooled for snap-cap fit. The graduation line is sharp and permanent; large, white, block-letters allow the labeling to be easily read. Features a large marking square. All sizes are supplied with a snap cap.