This item is a hard to find FOLDING ENGLISH SHOOTER WHISTLE/SHELL EXTRACTOR. The extractor is marked "12" for 12 gauge. These are a multi use tool for a hunter or gun enthusiast. It is a dual use item. The whistle was used to transmit commands to a hunting dog. The shell extractor was used for older shot guns that didn't have a mechanical shell extractor. Fired shells are hot and this device allow for hands free shell extraction. This particular one folds which adds to the scarcity. The chrome finish is slightly worn from long use. Opened, the whistle measures 3 3/8".