Locally made badges such as these, were often fashioned from used beer cans and were known as "beer can insignia". This insignia was worn on a black beret by a kind of South Vietnamese naval militia; men who owned small motorized sail boats (known as junks) who patrolled South Vietnam’s coastal waters to prevent infiltration of me, weapons and supplies down the coast for North Vietnam. The "junks" were usually armed with a machine gun and small arms. A small squadron had a South Vietnamese navy and a U.S. Navy advisor who could call for better armed backup if needed. The "Junk Force" stopped and searched hundreds of civilian vessels for contraband each day.