Falling Whistles
Falling Whistles sells whistles for $34 to $104 to raise money for education, advocacy, and the rehabilitation of war-affected people in Congo. The organization got its name from a journal written by its founder, sharing his experiences during a trip to eastern Congo in 2008. During that trip, Falling Whistles' founder met a group of five former child soldiers who told him that some children who were too young to carry weapons were sent into battle armed only with whistles. By wearing whistles, the campaign aims to use this weapon as a tool of protest and to raise awareness of the situation in Congo. As of September 2010, $500,000 has been raised.
Tin whistle
There are larger whistles, which by virtue of being longer and wider produce tones an octave (or in rare cases two octaves) lower. Whistles in this category are likely to be made of metal or plastic tubing, sometimes with a tuning-slide head, and are almost always referred to as "low whistles" but sometimes called "concert whistles". The low whistle operates on identical principles to the standard whistles, but musicians in the tradition may consider it a separate instrument.