Sharp O2 - Manual (Page 12)

11 Getting Started
5. Hold the battery so that the metal contacts of the
battery are facing down and the guides on the top of
the battery slide into the battery slots
, and then
insert it .
6. Replace the battery cover so that the marks are
aligned and slide it as shown.
Note
• Make sure that only 3V SIM cards are used.
• Use only the approved battery (XN-1BT10).