StarTech.com 1 Port Native ExpressCard RS232 Serial Adapter Card with 16950 UART - ExpressCard 54 Serial Card Add a high-speed RS-232 Serial port to your laptop computer via an ExpressCard expansion slot Expresscard Serial Card RS232 Card Compatible with both 34mm and 54mm ExpressCard slots; includes a slot spacer for greater security while installed in 54mm slots Single chip design optimizes speed, reliability and power