The original Galaxy tab did not come with a USB port! (I don't have a galaxy 2, so I don't know if they've corrected this or not, but I hope they have!) I don't know how you can make such a lovely tab and leave something so basic off. At any rate, these make up for it. There is a USB port that uses the 30-pin charging port and an SD card readerthat also uses the charging port. It's too bad you can't use these items while charging the unit, but at least you can transfer data and/or pictures to and from your tab. These work flawlessly and for me they were must-haves for my Galaxy tab.