In an attempt to protect line and junior officers from marksmen, the US Army authorized them to wear the enlisted sky blue mounted overcoats to make them harder to distinquish from the enlisted men. In order to make it easier for THEIR MEN to distinguish them, officers were authorized to wear collar insignia. These insignia were also found on other officer's garment. Sometimes only the insignia portion appears, omitting the border. These collar roundels are sold in pairs, by branch of service and rank. These pieces are a very subtle way to stand out.