A sphygmomanometer is a medical device used to measure blood pressure. It typically consists of an inflatable cuff to collapse and then releases the artery under the cuff in a controlled manner, and a mercury or aneroid manometer to measure the pressure.

Here are some common features and types of sphygmomanometers:

Cuff size: Sphygmomanometers come in various cuff sizes, and it is essential to choose the right size for accurate readings. Cuff size is determined by measuring the circumference of the upper arm.

Type of gauge: Sphygmomanometers can have a mercury gauge or an aneroid gauge. Mercury gauges are more accurate but also more expensive and fragile. Aneroid gauges are more affordable and portable but may need calibration from time to time.

Digital sphygmomanometers: Some modern sphygmomanometers have a digital display that provides readings in digital format, making them easier to read.

Stethoscope: Sphygmomanometers require the use of a stethoscope to listen to the blood flow in the artery. Some sphygmomanometers come with a built-in stethoscope, while others require a separate one.

Wall-mounted or portable: Some sphygmomanometers are designed to be mounted on a wall in a healthcare facility, while others are portable and can be carried around.

Manual or automatic: Manual sphygmomanometers require the user to inflate the cuff and release the pressure manually, while automatic sphygmomanometers inflate and deflate the cuff automatically.

Sphygmomanometers are commonly used in hospitals, clinics, and doctor's offices to monitor blood pressure. They can also be purchased for home use to monitor blood pressure at home. It is essential to follow the manufacturer's instructions for proper use and maintenance of the device.