This is an example of a World War I 25mm caliber Mark IV Very pistol used by the United States Army Air Service. The pistol is a direct copy of a French army design and was made by Scott Fetzer Machine Co. of Cleveland Ohio. Highlighted in this image is the gun barrel of a United States Army Air Service Mark IV Flare Pistol Barrel. Engraved on the barrel is Very Pistol 25 MM Mark IV Scott Fetzer Mach. Co. Cleveland.