The US government had caught wind of Dr Reinhardt's latest development in camouflage and needed to do the same to keep up with their superiority. Using "requsitioned" (read: stolen) Canadian technology, one US Army officer proudly presented what he calls "a modern camouflage pattern that can easily conceal it's users anywhere and will be used by the US Army for years to come". Despite badly failing every camouflage test by the army (final results said that the camouflage pattern actually made you shine brightly in every environment on Earth), it still managed to become standard issue to all US soldiers.
Rivet got his through an old contact he still has in the Army whom he claimed had ditched this perticular UCP fatigue for his older uniform because he hated it. He took because he thinks it looks cool.
Retextures Rivet's default tanker fatigues to the infamous UCP pattern. Good luck trying not to get spotted from the other side of Germany while you're wearing this.