AT&T Cingular Flip IV User Manual page 12

Inserting or removing the Nano SIM card and microSD™ card
To insert a Nano SIM or microSD card, push the Nano SIM or microSD card into
the corresponding card slot with the gold-connectors facing down . To remove
the Nano SIM or microSD card, push down on the plastic clip and pull the
Nano SIM or microSD card out .
Your phone only supports Nano SIM cards . Attempting to insert a Mini
or Micro SIM card may damage the phone .
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