Mac Sog Vietnam Skull Logo Embroidered Iron on Patch Measures 3 1/2" X 2 1/2". MACV-SOG was the joint service high command unconventional-warfare task force engaged in highly classified clandestine operations throughout Southeast Asia. It was given the title "Studies & Observation Group" as a cover. The joint staff was allegedly performing an analysis of the lessons learned to that point in the Vietnam War, but it was actually a special operations group with distinct command decision authority.