Shepherd's whistle
They are also produced commercially. Simple whistles may cost less than 1 USD in bulk; expensive ones may be quite ornate. They are commonly made of plastic, aluminum, stainless steel, silver, brass, titanium, Corian, jade, buffalo horn and other materials.
Omar Moreno
He considered a whistle used by his wife Sandra to be his most valuable heirloom from his playing days. The whistle made a very loud noise and was a common sound during the 1979 World Series broadcasts.