Tin whistle
In recent years a number of instrument builders have started lines of "high-end," hand-made whistles, which can cost hundreds of dollars US each — expensive in comparison to cheap whistles, but nevertheless cheaper than most other instruments. These companies are typically either a single individual or a very small group of craftsmen who work closely together. The instruments are distinguished from the inexpensive whistles in that each whistle is individually manufactured and "voiced" by a skilled person rather than made in a factory.
Whistle mix
A typical whistle mix is made from 70% potassium perchlorate and 30% sodium benzoate, measured by weight. The fuel in most whistle compositions is a salt of an organic acid. Compositions with chlorates and gallates were used historically, but have now been abandoned as prone to accidental ignition. These mixtures however, are less sensitive than the formerly used ones, which often contained mixtures with picric acid and potassium picrate.