Press the "Max/min" button once and the screen will display the highest temperature and humidity in the detection process. Press the "Max/min" button again and the screen will display the lowest temperature and humidity in the detection process. Outdoor temperature and humidity (outdoor temperature probe) will be displayed by default when the product is started. Press the "in/ out" button once to switch to indoor mode. Press the "alarm pattern" button for 2 seconds to convert the product into alarm setting mode. The maximum or minimum temperature range can be set. Once the range is exceeded, the alarm will be triggered. Press the "C/F" button once (the black button at of the product) to choose Celsius temperature and Fahrenheit temperature. If the Numbers on the screen are hard to read, it means the battery is low and you need to replace it.You need to reset the alarm Settings after replacing the battery. Name: Electronic Alarm Thermometer Error degree: 1 (33.8) Accuracy: 0.1 (32.18) Requires 1 AA battery, not included Indoor measurement range (IN): -10~50 (14~122) Probe measuring range (OUT): -50~70 (-58~158) size:63x63x14mm Material:ABS colour:White Package Contents: 1 x thermometer 1 x sensing line Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.