Marine Corps Service Aiguillettes with four loops are worn by aides to the President, Vice President, White House, and several high-ranking officials (Secretary or Deputy Secretary of Defense, Secretary or Under Secretary of the Navy, Assistant Secretaries of Defense or the Navy). They’re also worn by aides to the General Counsel of the Navy, Naval Attachés and assistant Attachés, Generals and Admirals (four stars), and representatives of foreign nations of appropriate rank.
Despite the name, Service Aiguillettes are authorized for wear on the Blue Dress (“C” and “D”) as well as on the “A,” “B,” and “C” Service uniforms. Unlike their Navy cousins, Marine Corps Service Aiguillettes are not authorized for wear on the all-weather coat or pullover sweater, nor may it be worn on the tanker jacket. Regardless of the side they’re worn on, Service Aiguillettes are fastened under the shoulder strap and encircle the shoulder under the armpit; the loop closest to the collar should be the longest.
All Service Aiguillettes are manufactured of round gold wire and scarlet cords. The scarlet can run if exposed to water and therefore the aiguillette should not be worn outdoors if there is precipitation or a likelihood of precipitation.