Pyrex® Viscosimeter volumetric flask of rugged mold blown construction, with a wide mouth and tooled rim. Flask is calibrated in accordance with ASTM specifications. U.S. Bureau of Mines Technical Paper 323B, No. 30.41; A.A.S.H.O. No. T 72; and "Gas Chemists Handbook," third edition, page 538. Reference: ASTM D-88 and E-102.