Pycnometer – Specific Gravity (SG) Flask with Teflon Stopper is used as a precise method used in density determination. Designed for use with a working liquid with well-known density, such as water to find the ratio of a mass to its volume (density). Specific gravity bottle is calibrated at 20°C. Calibrated by means of weighing contained purified water. Includes perforated stopper and features a flat bottom for spill prevention. Made of high quality Borosilicate 3.3 glass that is built to last and withstand multiple uses.