Enlisted airmen's chinstraps and visors are of plain black leather or polymer material. All commissioned officers' chinstraps are also of plain black leather or polymer material. The visors of company-grade officers (second lieutenant through captain) are plain black leather or polymer material. Field-grade officers' visors have two pairs of clouds and lightning bolts, patterned after the oak leaf motifs used by the other services. General officers' caps add an extra pair of clouds and bolts on the visor, while the cap of the Chief of Staff of the United States Air Force adds clouds and bolts around the entire cap band. The clouds and bolts are jokingly referred to in military slang as "farts and darts", much as the other services' oak leaf motifs are known as "scrambled eggs".