Valve has updated Team Fortress 2 to add cosmetic weapon effects. The Two Cities update kicks off with Manhattan which features a new map, changes to statistics reporting, more achievements, and Killstreak Kit drops that can add nifty cosmetic glows to your mayhem.
The loot you’ll get from completing a Tour of Duty will work a bit differently for the Two Cities Tour. Completing a Two Cities Tour automatically grants you a Killstreak Kit, which you can apply to any weapon to transform it into a Killstreak weapon. Completing the Tour also grants you a fabricator and spare parts that you can use to craft progressively rarer Killstreak Kits, which will add cool visual effects to your weapon and eventually even your character.
No doubt Killstreak Kits will be found in a Steam Marketplace near you!