Universal Camouflage Pattern Delta (UCP-D) was an experimental variant of the standard Universal Camouflage Pattern (UCP). It was tested by the U.S. Army around 2009 as part of efforts to improve camouflage effectiveness in Afghanistan, where the standard UCP was found to be lacking in concealment. It is arguably one of the greatest camouflage patterns the U.S. Army has ever cooked up. It was put into production during the mid to late 2000s for the war in Afghanistan. Preceding the release of multicam, this variant was incredibly popular when it was released and remains so to this day.
