Wireless connection for Wired speakers???

Are there any products that allow wired speakers to become wireless? I am sure there are, but I can't find anything. Any help or insight would be appreciated. Thank you.

Problem is amplification - it requires power, and depending on the speaker it could require a little or a lot of power. There are wireless speakers, but they're prefabricated. It's also not very practical. You won't get very long on a battery charge if the speakers are even halfway decent. Not very practical.