ExpressCard
ExpressCard, initially called NEWCARD, is an interface to connect peripheral devices to a computer, usually a laptop computer. The ExpressCard technical standard specifies the design of slots built into the computer and of expansion cards to insert in the slots. The cards contain electronic circuits and sometimes connectors for external devices. The ExpressCard standard replaces the PC Card (also known as PCMCIA) standards.
ExpressCards come in two form factors differentiated by the card widths, 34 mm and 54 mm. Although the width of the card is different, both cards use the same 26-pin contact connector. All ExpressCard/54 slots will except either ExpressCard/54 and ExpressCard/34 cards. Only ExpressCard/34 cards will fit an ExpressCard/34 slot.