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.
Physics of whistles
The yellow plastic pipe is actually a child’s toy that sounds when the pipe is whirled around. The metal pipe shown was used in the Concorde cockpit to provide cooling air to the pilots, but its loud tone got it canceled. This whistle is similar in many respects to the hole tone, in particular the teapot whistle. It is subject to frequency jumps and hysteresis loops. There are numerous articles on the internet about this whistle and it has been studied.