Welcome to GA 48.
This is a Steam Key.

NOTE - You need GameMaker: Studio PROFESSIONAL
in order to use this. NOT the free version.

I have read that the Free Ver will let you add this but It WILL NOT WORK
even if added. You need Pro. It says so right on the DLC page.

If you bought the Humble Bundle Like I did, this is already included with your Pro ver.
You also have an extra key like this that you don't need.
This key can be used by anyone who has the Pro ver but does not have this DLC.

Unlike most of the giveaways I've seen for this, I want to be clear who can actually use this.
The other giveaways are the same as this one, even if its not being mentioned.

If you have not read this but entered anyhow and can't use this. Then I'm sorry but that’s not my fault.
I'm making this L2 like all my other giveaways as I expect anyone at that level to be
more responsible then those who blindly click.

This is a good DLC for the right person. I hope this goes to someone who can use it.
Someone who has the Pro version but missed the HB bundle and wants this.