In the aneroid sphygmomanometer, an aneroid gauge replaces the mercury column.

The aneroid gauge consists of a bellows connected to a dial pointer. An increase in the pressure expands the bellows (Fig 2). This expansion of the bellows is translated to the dial pointer, which moves across the scale to indicate the pressure. The accuracy of the aneroid sphygmomanometer declines with use due to physical defects in the casing and tubing or the indicator needle drifting from zero.