The whistle is correct for the First World War period with the patent number 5727.08 stamped to the top which as discontinued in 1920. The whistle is in good original condition and in good working order. The exterior of the case is stamped.Please look at my other items for more militaria and collectables. This item is in the category "Collectables\Militaria\World War I (1914-1918)\Field Gear". The seller is "1928thompson" and is located in this country: GB. This item can be shipped to North, South, or Latin America, all countries in Europe, all countries in continental Asia, Australia.