similar to the Royal Air Force design, except that the coat and trousers are dark blue. Dark blue bow ties and dark blue cummerbunds are used for black-tie affairs, and white bow ties with white waistcoats for white-tie affairs. Silver-trimmed shoulder boards and silver sleeve braid are worn rather than rank braids (enlisted members wear sleeve rank insignia instead of shoulder boards, and no silver sleeve braid), along with silver buttons. No hat is worn. General officers have solid silver shoulder boards and wider silver sleeve braid. Enlisted members also have the option to wear the semi-formal uniform, essentially an issued service dress with a white shirt substituted for the blue shirt, but many non-commissioned officers elect to purchase a mess dress. Women's mess dress uniforms have a long skirt replacing the trousers and delete the button chain clasp for the coat. As of August 2020, females have the option to wear mess dress trousers. Members of the Civil Air Patrol, the United States Air Force Auxiliary, may wear the U.S. Air Force mess dress uniform with distinctive Civil Air Patrol insignia and trim. The Civil Air Patrol mess dress uniform is identical to the U.S. Air Force mess dress uniform, except that the silver braid on the jacket and officer rank insignia (shoulder boards) of the U.S. Air Force mess dress uniform is replaced with dark blue braid, and a Civil Air Patrol seal device 3" in size (either embroidered in bullion or finished in enamel) is worn in place of the middle button on the right side of the jacket. Members of the Civil Air Patrol NCO corps wear distinctive Civil Air Patrol NCO rank insignia in lieu of U.S. Air Force NCO rank insignia. Civil Air Patrol cadets do not wear the U.S. Air Force mess dress uniform, but may wear the semi-formal uniform described above for U.S. Air Force enlisted members, or a modified semi-formal dress uniform consisting of the old-style U.S. Air Force service uniform (with the four button jacket with patch-type pockets) with the name-tag removed and with Civil Air Patrol distinctive insignia, a white dress shirt, and a bow-tie (either black or U.S. Air Force satin blue). Civil Air Patrol senior members do not wear these semi-formal uniforms, but instead may wear a civilian equivalent consisting of a blue jacket, grey trousers, white dress shirt with a black bow-tie, and distinctive Civil Air