This product can be used with batteries or connected to a power outlet. 【Multi-function】Alarm function, alarm auto-stop, 12/24 hour display switchable, calendar, temperature display, humidity display, and afterglow light. 【Sound Sensor and Energy-Saving Function】Can be set to display in response to sounds of 60dB or higher. The display brightness is halved from 6 PM to 7 AM the next morning. 【Setting Memory】Even if the power is cut off, the time and settings are remembered thanks to a built-in lithium battery, although the display will turn off. 【Picturesque Wood Grain】The warm wood grain is natural and blends into any space. It can be placed in various locations, such as the living room, bedroom, computer desk, children's room, or guest room. 【Two Power Supply Methods】USB/Batteries. Batteries can be used, but they only last for about 1 to 3 days. We recommend using rechargeable batteries if using batteries. Please use USB power (power from a household outlet) as the primary method. If using batteries, please use voice mode (for energy saving).