Unzip help.

I have been trying to write a rule that will unzip any file placed in my Downloads folder without success. I have tried without success:
If extension is zip
Unarchive
I guess that this is probably far too simple, any help or hints would be much appreciated. Cheers.
If extension is zip
Unarchive
I guess that this is probably far too simple, any help or hints would be much appreciated. Cheers.