Four of the items are purely cosmetic while the others are actually serviceable in combat. They're available through the Mann Co. store. Purity Fist anyone?
The Machina, Diamondback, Widowmaker and Short Circuit are each weapons with various 'augmentations' you could say. There's also four purely cosmetic items that look rather fetching for the free-to-play shooter.
For a full run down of the pre-order goodies visit the. Deus Ex: Human Revolution releases on Xbox 360, PS3 and PC August 23rd in the US.