A pulse oximeter is a non-invasive medical device that measures:

1. Oxygen saturation (SpO2): The percentage of hemoglobin in your blood that's carrying oxygen.
2. Pulse rate (PR): Your heart rate, measured in beats per minute (bpm).

To use an oximeter:

1. Place your finger on the sensor, usually a clip-like device.
2. Ensure a snug fit, but not too tight.
3. Wait for the device to display your readings (usually takes a few seconds).
4. Record your results, if desired.

Oximeters are commonly used:

- In medical settings to monitor patients
- By athletes to optimize performance
- By individuals with respiratory or cardiovascular conditions
- At high altitudes to monitor oxygen levels

Remember, pulse oximeters are not a substitute for medical diagnosis or treatment. If you have concerns, consult a healthcare professional.