The FLX USB drive prototype, designed by Jacek Ryn, while convenient, is not actually flexible. It's got an accordion-like sheath covering it that pushes back to reveal the plug when you shove it into the USB port, and snaps back when you pull it out. Kind of like an uncircumcised, um, you know. And that cuts down on plastic materials, so it takes up less space in your pocket. Yep. [core77]
The big news, unless you work at the slime pits, is that usb sticks don't need caps. I have been carrying these things around since the 90's, I throw the caps away. Useless.
If you really want to hide or 'protect' your plug there are prettier solutions, this thing is farking ugly.