Twist the cover counter clockwise and remove it.
Locate the batteries (in the compartment marked with the warning sign).
Slide off the cover of the battery slot.
Gently remove the batteries.
Note the battery terminals (+, -).
Place new batteries in the device (CR123A).
Replace the cover on the battery slot.
Note the three notches on circumference of the device and the small node at the top.
Line the node up with the arrow on the inside of the base.
Press the cover onto the base and twist clockwise until you hear a click.