Specification:Item Type: ClockMaterial: ABSSize: Approx. 23x9.3cm / 9.1x3.7inGross Weight: Approx. 229g/8.1ozBattery: 1 x CR2032 Button Cell (Not Included)Power Supply: USB Power SupplyHow to Use:1. Connect the power supply.2. Control the clock switch and functions through the buttons on the product.Package List:1 x Clock (Battery Not Included)1 x USB Cable1 x Instruction ManualNote:1. Please allow some error due to manual measurement.2. Memory function, will keep the time data when the power is off, no need to plug in again to set the time.3. The built in battery records time in the event of a power failure, and the clock is powered by the USB cable only.4. Please read the instruction manual before using this product and keep it in a safe place for future use.5. When the external power supply is turned off, the internal power supply starts to supply, the clock is timing normally, but the LED screen has no display and enters the power saving mode.