Have purchased the unit for Lexar 16GB Mobile MicroSDHC Card Class 6 High-Speed Micro SDHC Upto 10MB / s Write and upto 18MB / s Read with free SD adapter and High Speed USB Reader card because the supplied USB SD Card Reader as large and was clunky. The card reader is tiny and reached when the card the same read / write values as with other devices, ie, the maximum out of my map extract (9MB / s write and to 16MB / s read) For the money and the size super thing :)