Features of the Thermometer: 1. Accurate Measurement: Measurement accuracy ≤ ±0.1°C. (Using imported infrared detection system) 2. Service Life: Equipped with 1 AA battery, it can be used for more than 100,000 times, with a product life of >300,000 times. 3. Easy to Use: One-button measurement, convenient operation. 4. Non-contact: Measurement on the forehead without touching the skin. 5. Quick Temperature Measurement: Measurement time is 0.5 seconds. 6. Measurement Distance: Adapts within 5-15 cm, no fixed measurement distance required. 7. Large Display: Large LCD display with white backlight, clear display under any light. 8. Temperature Difference Setting: Set the temperature difference between indoor and outdoor to avoid environmental impact on instrument test data. 9. Data Storage: Stores 32 measurement data, convenient for analysis and reference comparison. 10. 2 Modes: Daytime and Nighttime modes for convenient operation. 11. Unit Conversion: Converts between Celsius and Fahrenheit. 12. Large DisplayBacklit LCD display for easy reading during testing. 13 large capacity batteries. One 9V battery is equivalent to several times the capacity of a standard AA 5-volt battery. Safety precautions: ● Please read this manual carefully before use. ● Use the product within an ambient temperature range of 10 to 40 degrees Celsius. ● Do not place the product near electrically charged objects to avoid electric shock. ● Do not use the product in environments with relative humidity greater than 85%. ● To clean, use alcohol to gently wipe the surface of the instrument. ● If there is a problem with the product, please contact the distributor and do not attempt to repair it yourself. Additional instructions: The non-contact infrared thermometer is a professional thermometer designed to measure human body temperature. It can be used by consumers in home settings and by medical personnel in clinics. It meets the ASTM1965-1998 standard. HT820 is specifically for non-contact infrared thermometers for human measurements. It meets medical directive 93/42/EEC. Normal body temperature ranges for different measurement positions: Human body temperature varies throughout the day.The temperature is also affected by other external conditions, such as age, gender, skin color, and thickness.? Normal body temperature in Celsius is 36-37°C, and in Fahrenheit is 97.8-100.4°F.? Normal body temperature in the anus is 36.6-38°C, and in the mouth is 35.5-37.5°C.? Normal body temperature under the armpit is 34.7-37.3°C, and in the ear is 35.8-38°C.? The normal body temperature range for different age groups is:?