Sony Micro Valute USM 16 GR 16 GB Pen drive even slower than a "Class 4" memory card. It’s peak writing speed is 4 MB’s for large files like movies, and average about 3 MB’s. It is the slowest pen drive I have seen, good speed when read but very very slow during write. It tooks 2hrs for 4 GB. Very poor built quality. Not a real Sony product, it is labelled as a Chinese product on it’s product cover. Don’t waste your money on this pen drive.