Each shirt qualifies as a piece of level 10 armor, with other stats that are appropriate to the faction in question. (Expect the Techs shirt to offer bonuses to crafting rather than combat bonuses, for example.) The vouchers can be turned in at any time, and should the player later decide they'd prefer to represent someone else, a shirt may be turned in and exchanged for another shirt as well. It's nothing game-breaking, but yet another added incentive to pick up Fallen Earth and see what all the fuss is about. Still not quite as good-looking as the hat, of course, but you have to draw the line somewhere.