In English, this device is called a Pulse Oximeter. ​Here is a quick overview of how it works and what the readings mean: ​What is a Pulse Oximeter? ​It is a small, non-invasive clip-on device that measures your Oxygen Saturation level (SpO2) and your Heart Rate (Pulse). It works by shining a light through your skin to detect how much oxygen is in your red blood cells. ​Key Readings on the Screen ​When you put your finger in the device, you will see two main numbers: ​SpO2%: This is your blood oxygen level. ​PR (BPM): This stands for Pulse Rate in Beats Per Minute (your heart rate). ​What are Normal Levels? ​Normal Oxygen Range: Typically between 95% and 100%. ​Low Oxygen: If the level drops to 92% or below, it may indicate a medical issue, and you should contact a healthcare provider. ​Normal Resting Heart Rate: For most adults, this is between 60 and 100 BPM. ​How to Use It Correctly ​Preparation: Make sure your hand is warm and your finger is clean. ​Placement: Clip the device onto your middle or index finger. ​Stillness: Keep your hand still and resting below the level of your heart. ​Wait: Wait a few seconds until the numbers stop jumping and show a steady result. ​Common Factors That Affect Accuracy ​Nail Polish: Dark colors or gel nails can block the light and lead to false readings. ​Cold Hands: Poor circulation due to cold weather can make it difficult for the device to get a pulse. ​Movement: Shaking or moving your hand during the test will result in an error or inaccurate data. ​Bright Light: Very bright direct sunlight hitting the sensor can sometimes interfere with the infrared light. ​Since you are learning about medical tools and currently working as a cashier—where you likely use your hands a lot—remember that keeping your fingers relaxed and free of any coverings (like tape or bandages) is key to getting a good reading with this device. ​Would you like to know which finger is scientifically proven to give the most accurate reading