Specification: Material: Plastic Host Size: Approx. 20 x 9.3cm / 7.9 x 3.7in Battery Type: 1 x NCR18650B Lithium Battery Pack (not included) Power Supply: USB cable connection to adapter, power bank, car USB interface, etc. How to Use: 1. Power supply: ①External power supply: When there is no built in lithium battery in the main unit, connect the power adapter or USB power supply, and the machine will make a "beep" sound to indicate that it is powered on. At the same time, the machine will automatically detect if the battery is installed. If there is no battery, the battery level is displayed as full on the screen. 2. Power On/Off: ①Power on: Press the "Power button" for 1 second to turn on the machine. After a beep sound, the screen will light up, displaying the current temperature inside the box, as well as the battery level and fan status. ②Power off: Long press the "Power button" for 3 seconds to turn off the machine. After turning off, if there is a battery in the machine, only the battery level indicator will be displayed on the screen. 3. Temperature setting: The temperature setting range of the refrigerator box is 0-18℃. Press the "increase" or "decrease" button directly, and the temperature will flash. At this time, you can set the desired refrigeration temperature. Power supply methods: 2. USB power cable: It can be connected to a mobile phone USB charger, power bank, or car USB converter. When using USB, pay attention to the voltage of 5V and at least 2.1A, otherwise it may cause damage. Troubleshooting: 2. The displayed temperature exceeds 30 degrees: Check if the fan is working and if the ventilation holes are blocked. 3. The temperature is not cold enough: Check the set temperature, check if the heat dissipation holes are blocked, if the ambient temperature exceeds 35 degrees, if the cover is opened too many times, or if it is open for too long. 4. The screen displays E1: Temperature sensor failure, the temperature sensor needs to be replaced. 5. Excessive noise: Check if there are any foreign objects inside the fan.