Patent ID: 7431609

Claim:
A portable electronic device comprising: a main body comprising a first side wall and a bottom wall, the first side wall defining at least one receptacle and at least one hole therein, the at least one receptacle comprising a cavity and a slot, the cavity spanning from the bottom wall up into the main body, the slot being defined upwardly in a part of the first side wall, the slot intercommunicating between the cavity and an exterior of the first side wall; and a subsidiary casing comprising a base and a cover, at least one latch and at least one connector being formed on the base, the at least one latch being configured for being received in the at least one receptacle, the at least one connector being configured for being received in the at least one hole; wherein the base includes a plurality of second side walls, the at least one latch is formed on one of the second side walls, and the cover includes a plurality of third side walls; wherein one of the at least one latch extends from the one second side wall to one of the third side walls and a part of the one latch is above the one second side wall.