A sphygymomanometer is a blood pressure cuff blood oxygen meter tool measuring heart rete stethoscope

## Step 1<br />A sphygmomanometer is a device used to measure blood pressure. It consists of an inflatable cuff to restrict blood flow, a measuring unit to display the pressure, and a mechanism for inflation which may be a manually operated bulb and valve or an automatic pump.<br />## Step 2<br />The other options provided, such as a blood oxygen meter, a tool measuring heart rate, and a stethoscope, are not correct. A blood oxygen meter measures the amount of oxygen in the blood, a tool measuring heart rate measures the number of heartbeats per minute, and a stethoscope is used to listen to the sounds made by the heart, lungs, and other organs in the body.<br />## Step 3<br />Therefore, the correct answer is "blood pressure cuff".