The X635 or KAC PDW is an experimental personal defense weapon somewhere between a rifle and a SMG. The odd 6x35 mm round has not been produced in any large quantities because of the experimental nature. The 6x35 mm round in the game's sense means somewhere between a rifle and SMG cartridge and therefore high power and high fire rate. The PDW is decent overall and has only -1 mobility making the weapon very quick and effective in many situations.