A mobile phone may include a housing, a battery at least partially within the housing, and a circuit board assembly at least partially within the housing and positioned along a side of the battery. The circuit board assembly may include a first circuit board defining a first hole, a second circuit board defining a second hole, a wall structure between the first circuit board and the second circuit board and attached to an inner surface of the first circuit board and an inner surface of the second circuit board, and a fastener assembly configured to retain the first circuit board to the second circuit board.