The Fairbairn-Sykes Fighting Knife is a double-edged knife with a foil grip developed by William Ewart Fairbairn and Eric Anthony Sykes in Shanghai before World War II, but made famous during the War when issued to British Commandos, including the SAS. Source: Wikipedia
The blade on the John Nowill & Sons Ltd, Fairbairn Sykes Commando knife features a double edged black carbon steel blade.
The handle on this British Commando knife is made of non-magnetic alloy and the grip features 27 concentric rings and a crossed key trade mark. The pommel nut is hexagonal and the guard is stamped with "John Nowill & Sons Sheffield England" and an arrow symbol and a diamond with an H in the middle.
Black leather sheath with a 2 1/4" slots to pass a belt through. The sheath also has four small leather tabs (two on each side) to allow it to be sewn to equipment or clothing. The bottom of the sheath has a metal tip. The knife is secured to the sheath by use of an elastic which is stretched over the handle of the knife.