Historical Images & Videos on Instagram: "The whistle is produced when air is forced through a small opening in the lips or between the fingers, generating sound vibrations. The position of the tongue and the shape of the mouth are essential for directing the airflow and creating different tones. With practice, it’s possible to adjust the intensity and frequency of the sound, modulating the whistle."

Heng Yue（岳阳新刺客） on Instagram: "frequency adjustable machine with Dragonhawk. With the ability to adjust frequency from 3Hz to150Hz. #tattoo #tattooart #tattooartist #blackandgrey #blackandgreytattoo #tattoomachine #tattoodesign #freehand #tattoodo #orientaltattoo #asiantattoo #tattooer #tattooing #岳阳新刺客 #tattooistartmag #tattoosketch #chinesetattoo #纹身 #刺青 #hengyue"