Here you can buy the key Outlast: Whistleblower DLC (addition to Outlast) at a bargain price. After purchase, you will immediately receive a key, activating which you will add DLC to the game Outlast to your steam account.
Without the original Outlast game on your account, you will not be able to activate the Whistleblower DLC add-on.
http://store.steampowered.com/app/273300/Outlast_Whistleblower_DLC/
You can activate the key in any region.
Steam