Here is a trench coat;
A trench coat is a stylish and popular item of clothing worn round the world. It is generally made of heavy duty cotton, drill or poplin, and has a removable lining, depending on the place it is being worn in.
It is a descendant of the heavy serge coats worn by British, Canadian and French soldiers in World War I. Towards the Second World War, the trench coat became part of all enlisted men's and officer's kit, especially in the American forces: the US Army, US Army Air Corps, and the US Marine Corps.
The typical trench coat is as follows; a ten buttoned double breasted long tan, khaki or beige coat with cuff straps on the sleeves, epaulets (originally used to hold gloves and the folding service cap found on the heads of enlisted and commissioned personnel in American, British and Canadian Forces in the Second World War and the Korean Police action: and its scottish made relative, the Glengarry Bonnet), and a belt that may also have two small brass D-rings as a salute to its military heritage; the rings originally were used to secure grenades, sidearms and/or swords.
Here is another.