Designed after the original and vintage bosun whistles of days gone by, this 1-3/4"" vintage brass and copper antique bosun whistle reproduction on a 2-1/2" chain is truly an inexpensive, remarkable gift for a former/present sailor, nautical enthusiast, history teacher or naval academy graduate or seaman. A boatswain's call, pipe or bosun's whistle is a pipe or a non-diaphragm type whistle used on naval ships by a boatswain. It is pronounced, and sometimes spelled, "bosun's call". The pipe consists of a narrow tube (the gun) which directs air over a metal sphere (the buoy) with a hole in the top. The player opens and closes the hand over the hole to change the pitch. The rest of the pipe consists of a "keel", a flat piece of metal beneath the gun that holds the call together, and the "shackle".