Wide Front Sight Base Gas Cylinder that has a flat on the rear ring with a letter code, a punch mark on the bayonet lug(Some also have a letter or number on the lug) and a dimple on the right rear just behind the stacking swivel screw. These were observed on Springfield Armory Rifles 2M. to 3.8M during WWII. These cylinders have been refinished using the original DuLite or black oxide process, they are beautiful. The the bores have been USGI gauged and are good to very good. They come with their original Stacking Swivel and will fit any Garand. These are very nice gas cylinders aimed at the collector and shooter alike. Check out the great pricing on multiples of these cylinders!