PCMCIA
The REX 6000 was an ultra-thin PDA produced by Xircom. It was the world's smallest full-function PDA due to its size as a Type II PC Card. The REX synchronized by insertion into a host PC's PCMCIA/PC Card slot. The REX 6000 was similar to its predecessor (the Franklin REX 5000) except it included a touch screen, among other improvements.