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.
Whistling
According to Guinness World Records, the highest pitch human whistle ever recorded was measured at 4,186 Hz, which corresponds to a C8 musical note. This was done by Michael Stuart in Richmond, Virginia, on January 11, 2016. The lowest pitch whistle ever recorded was measured at 174.6 Hz, which corresponds to a F3 musical note. This was accomplished by Jennifer Davies of Dachau, Germany on November 6, 2005. The most people whistling simultaneously was 853, which was organized at the Spring Harvest event at Minehead, UK on April 11, 2014.