This is supposed to be an authentic Microsoft product. The one I got from Mambate is not. I paid $88+, for a cheap knockoff that they're selling for $56. Buy.com evidently doesn't have much control over their partners in crime.
I guess it is all about getting a low price point when they sell the game console, so when we got the XBOX it had almost no hard drive space. IMHO, Micro$oft should have shipped the XBOX with this as a minimum. Having the game on a hard drive instead of on disc makes gameplay much faster. Suddenly I wasn't losing as often in COD! If you plan to play online competitively, you need this.