Mercurial Sphygmomanometer. (Manual Blood pressure meter)

Should be operated by a trained person. Mercury manometers are considered to be the "gold standard" of measurement because their measurement is absolute and does not require re-calibration.

For this reason they are often required in clinical trials of pharmaceuticals and for clinical evaluations of determining blood pressure for high risk patients including pregnant women.

Aneroid, mechanical types are in common use, but they should be calibrated against a mercury manometer.

The unit of measurement of blood pressure is millimeters of mercury (mmHg).

Blood pressures are usually given as an even number.^{[citation needed]}

Manual sphygmomanometers require a stethoscope for auscultation.