The Navy first authorized a khaki uniform in 1913 as a practical garment for early naval aviators; they were given permission to wear Marine Corps khaki uniforms with naval insignia, when flying or working on aircraft. Khakis were authorized aboard submarines in 1931 and as a working uniform on all ships ten years later. The Service Khaki uniform today is the sole province of commissioned officers in grades O-1 through O-10, chief warrant officers in grades W-2 through W-5 (the W-1 grade is not currently in use in the U.S. Navy) and chief petty officers (also known as CPOs) in grades E-7 through E-9. It is a khaki button-up shirt and trousers, worn with a gold belt buckle. The shirt features two front flap pockets and a pointed collar. The suit includes jacket, dress shirt, and pants. Optional Accessories: * Khaki web belt * Corcoran dress shoes.