Projection Alarm Clock Innovative Mute Digital Alarm Clock Projector with Indoor Thermometer Hygrometer for Bedroom Item Type: Projection Alarm Clock Material: Plastic Usage: 1. Plug in the USB cable e 2. Use the battery Battery Note: 2 x AAA Batteries (Not Shipped with Batteries) Alarm clock should not use high capacity alkaline batteries (such as for Nanfu batteries), please use ordinary carbon batteries, otherwise it is easy to appear chaotic appearance, because high capacity batteries easily burned circuit boards! The brightness of the screen is brighter when using the battery than when using the power supply. Do not turn on/off the alarm clock (power or battery mode) often, otherwise it may not work temporarily, then stop the alarm clock for more than 30 minutes before turning on the power or battery.