United States Navy ratings are general enlisted occupations used by the U.S. Navy from the 18th century, which consisted of specific skills and abilities. Each naval rating has its own specialty badge, which is worn on the left sleeve of the uniform by each enlisted person in that particular field. Working uniforms, such as coveralls and the camouflage Naval Working Uniform, bear generic rate designators with no rating insignia attached. For a brief period from September 2016 to December 2016, ratings were not used. However, they were reintroduced in December 2016 and remain in use. U.S. naval ratings are the equivalent of military occupational specialty codes (MOS Codes) used by the United States Army and the United States Marine Corps, the ratings system used by the United States Coast Guard, and Air Force Specialty Codes (AFSC) used by the United States Air Force.