**The difference between battery, USB, plug and remote control** Battery: Use 2AA or 3AA batteries, put the batteries into the battery box, the cotton ball will light up. USB: Applicable to devices with USB socket, such as: laptop USB socket, USB socket, link to powered USB socket, the daisy chain will light up. Plug:The plug must be plugged into a live AC outlet for the light to turn on. Control (Remote control): For the model with remote control, the batteries must be placed in the battery box. The remote control can turn the ball light on and off at any time.