The U510 from PQI of Taiwan has made a VERY slim flash drive. In my never-ending quest to find everything small that exists in the universe, my eye lit on this item. It’s 3 millimeters thick and is a big 16 GB in a small flat credit card size drive. Connect to a Windows or Mac OS system via the retractable USB 2.0 connector. I wouldn’t want to put this in a back pocket, however. What if I sit on it and it breaks.