Original Apple, fully tested 8MB RAM card for the factory installed slot of the PowerBook 1400 series.
The 1400 logic board has two RAM slots which take different, non-interchangeable modules. The first is referred to by Apple as the factory slot and was pre-populated by a 4 or 8MB card as standard. Although it was easily accessible on the 117MHx model, the larger 133MHz and 166MHz processor boards meant that the slot could not be accessed without removing the processor board.
The second slot, referred to as the customer or user slot, is easily accessed on all models by simple removing the heat sink. The PowerBook supports up to two piggy backed user RAM boards.