The Proof of Purchase

This item was initially given to players who purchased Team Fortress 2 before the Über Update on June 23, 2011, but can still be obtained by receiving a gift of the game, or by activating a retail copy of the game - such as purchasing The Orange Box.

There are over 10,000+ instances of this item (and counting up).

The Proof of Purchase

Team Fortress 2
Team Fortress 2 Level 50 Helmet
From another era.
 
( Not Tradable or Marketable )
Tags: Unique, Cosmetic, Scout, Sniper, Soldier, Demoman, Medic, Heavy, Pyro, Spy, Engineer, Not Tradable, Not Marketable