At $50.00 each and as delicate a rose, this is the glass hydrometer to use if you want to measure your SG/Density to an accuracy of 0.0005
Fisherbrand* ASTM* Specific Gravity Hydrometers for Liquids Heavier than Water > ASTM: 111H; Range: 1.000 to 1.050
Hydrometer, Specific Gravity; Fisherbrand ASTM; For Liquids Heavier than Water; ASTM: 111H;Range: 1.000 to 1.050; Division: 0.0005; 330mm L; Made from polycarbonate for glass-like clarity; Use with11-582-1 Cylinder
God I love lab gear.
http://www.fishersci.com/wps/portal/...e&fromSearch=Y