Start with that much; the key is not completely invisible, it will exceed a few millimeters from your PC (5 or 6), but it should be enough to avoid hang or damage. It should nevertheless take some precautions, especially when one puts his laptop in his bag (or the touch pad, for those who had the good idea to keep a USB port). However, if you want to use a facade with a USB camera (they are becoming more numerous DVD / Blu-Ray Players, radio, television, internet Box, tuner / recorder TNT, gateway multimedia), it will could not be more discreet and strictly not constitute any discomfort. As for performance, here are the values which I could measure; 4 minutes 05 to write a (big) 1GB file (3.85 MB / second) is not that bad. it rises to 15.2 MB / second read for the same file. 5 minutes 35 for a complete picture folder, 900 MB (37 subfolders, 1256 files) or 3.18 MB / second and 57 seconds to read the same folder (18.82 MB / sec). It is close to the theoretical values announced by the manufacturer (6.5 MB / s write, 16MB / s read) data or test software (4.08 MB / sec writing, 18MB / sec read) . A speed or file sizes increase, do not hesitate to make a version of high capacity, prices are not excessive. Finally, the only downside is the risk of losing the cap ... because once the key inserted permanently into a USB port, we do not know what to do.