The back-up battery will power the Home Base for a period of time should the A/C power to the device be cut off.
INSTRUCTIONS & INFO
Remove the bottom of the device by pressing down and sliding the entire cover in the direction of the Indicator arrows, as shown. Then, gently pull the cover up.
Insert the Back-up battery by aligning the gold contacts on the battery with the gold contacts on the device.
Replace the Bottom cover by placing it over the device with the Back label facing the device ports. Then, slide downward in the direction opposite the Indicator arrows. The cover should snap into place.