This is a CD KEY for the game Prototype 2 on steam.
This requires a free steam account to be able to download and play.
The cd key will be sent to you within 12 hours of purchase via ebay message. (but usually much sooner - 1-2hours typically)
Again this is a DOWNLOAD, you will be given a cd key via email to be redeemed on the steam client which will allow you to download and play the game.
Any questions please ask.