Collar grade insignia are worn by commissioned officers in three branches of the Armed Forces of the United States: Navy, Marine Corps, and Coast Guard. For the O-1 grade, designated as Ensign in the Navy and Coast Guard and 2nd Lieutenant in the Marines, this consists of a single gold bar; the same insignia is used for 2nd Lieutenants in the Army and Air Force but is not worn as a collar device.
Following the discontinuation of several types of uniforms in 2006, Ensigns in the Navy wear collar grade insignia only with short-sleeve shirt worn with the Service Khaki uniform. Ensigns who are Line officers wear the insignia on both collar points, while those serving in a Staff Corps wear the insignia of grade on the right collar point and the staff insignia on the left. In the Coast Guard, Ensigns wear collar insignia with the Winter Dress Blue uniform (mandatory), as well as on the light blue shirt worn with the Service Dress Blue uniform when the jacket is removed. Ensigns serving in the Coast Guard Band wear collar grade insignia with the Concert Dress Uniform and the Ceremonial Uniform.
Marine Corps regulations call for 2nd Lieutenants to wear collar grade insignia on the collars of khaki shirts (even when worn under sweaters) and utility and camouflage maternity coats. Collar grade insignia must be worn at all times when officers are wearing the Service “A” uniform. For camouflage and utility uniforms, commanders may prescribe drab-brown insignia to replace gold-color insignia worn by 2nd Lieutenants and Majors.