Ahem. It's an adapter for connecting normal 100BaseTX-networks to the mains. The adapter is often used as a LART. It can be used as office ornament for sysadmins, or simply fun for you and your friends.
Etherkillers have devastating effects on network equipment, and the result will be anything from a slightly fried network card, to a completely fried computer, depending on the chips used, and your luck.
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