G-Shock MRG-8100B-1A - Manual (Page 90)

89
Battery
The special rechargeable battery used by your watch is not intended • •
to be removed or replaced by you. Use of a rechargeable battery
other than the special one specified for this watch can damage
the watch.
The rechargeable battery is charged when the solar cell is exposed
• •
to light, and so regular periodic replacement is not required. However,
charging and discharging of the battery over the years leads naturally
to a loss in its ability to sustain a charge and shortens its operating
time. If this happens, contact your original retailer or authorized
CASIO service center.