Fish hook designs, shapes, and materials are all variable depending on the intended purpose of the fish hook. Fish hooks are manufactured for a range of purposes from general fishing to extremely limited and specialized applications. Fish hooks are designed to hold various types of artificial, processed, dead or live baits (bait fishing); to act as the foundation for artificial representations of fish prey (fly fishing); or to be attached to or integrated into other devices that represent fish prey (lure fishing). The fish hook or similar device has been made by man for many thousands of years. The world's oldest fish
Fly-killing device rackets, which became popular worldwide in the late 1990s. US Patent 5,519,963 was awarded to Taiwanese inventor Tsao-i Shih in 1996 for such a device. The handle contains a battery-powered high-voltage generator. The circuit is composed of an electronic oscillator, a step-up transformer and a voltage multiplier, similar to the circuit in an electroshock weapon or stun gun, but with much lower power. The grid of the flyswatter is electrically charged to a voltage of between 500 and 1500 volts (V) of direct current, activated by pressing and holding a button. When the electrically conductive body of a fly nearly