function. This clock supplies four USB charging hubs or three AAA batteries. It is a great assitant with rich functions for you. When you are outside, you can also leave a message on the board to your family. Or you can set at some points of one day to ring automatically happy birthday song. Specifications: Material: Plastic Appearance of watch: white Pen Color: Blue, Green Display screen: LED screen Power supply: USB charging port or AAA battery( Batteries not included) Calendar query from 2000-2099 Item size: 142x65x135mm Note: Light will be on all the time if it is powered by DC 5V; otherwise it will be off after 10 seconds. Package includes: 1 x LED Message Board 1 x Pen 1 x USB Cable