Many families have also begun to purchase and use blood pressure monitors. The commonly used sphygmomanometers come in three types: mercury column sphygmomanometers, electronic sphygmomanometers, and aneroid sphygmomanometers. Although only the mercury column sphygmomanometer can accurately measure blood pressure values, it is relatively difficult to operate as it requires listening through the ears and observing the systolic and diastolic blood pressure values in a relatively quiet environment. Therefore, currently almost all families use the relatively simpler-to-operate electronic blood pressure monitor.