For specific gravity of road oils, road tars, soft tar pitches, and asphalt cements according to ASTM D70, AASHTO T43; drying oils, varnishes, resins, and related materials (ASTM D1963); water and brine (ASTM D1429); and insulating varnishes (ASTM D115)

Stopper is concave on underside and has hole, approx. 1.6 mm in diameter, to allow air to escape.