The U.S. role grows "... ARVN regimental headquarters northeast of Saigon in January 1960 Americans in Vietnam begin to plan for increased U.S. aid to Diem." http://www.britannica.com/EBchecked/topic/628478/Vietnam-War/234631/The-US-role-grows
A U.S. Marine in 1966. He wears a first pattern M1955 flak vest, as well as M56 ammo pouches and Army issue M1945 suspenders. His helmet cover is the WWII issue cover with an integral insect net, shown here tucked inside the helmet.