1) Press down on release button A to slide down the battery cover B.
2) If used batteries are present, remove these batteries from the unit by pulling up on one end of each battery. DO NOT remove or install batteries using sharp or metal tools. Install new batteries as shown in the polarity diagram (+/-) inside the battery compartment.
3) Replace battery door securely.

NOTE: Only the controller would need batteries. The Extreme Air Board includes a rechargeable battery.