And a key can be there in your backpack if you are emailer #52 to us. Subject should be #52, include your steam name, email only once. Anything other than that and if you happen to be #52 you won't win.
Today's key was won by Jerrinho11. He was the 52nd person to send us one email with "#52" in the subject and his steam name in the body. Congratulations to Jerrinho11 and good luck to everyone for tomorrow's free key (details here).