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.
Trainwreck Circuits
, Trainwreck amplifiers fetch $25,000 and up. His amps are praised for the simplicity of their design and their touch sensitivity: "The sound's so immediate from the pick to coming out of the amp, [which] opens up a whole new kind of playing", according to Charles Daughtry (Kaylene's owner, who sold all his Dumbles to build a collection of six Trainwrecks). Fischer's circuits were simple yet original, and he took extraordinary care in selecting the individual electronic components.