Do common rubber bands qualify as devises? They sure work for me, as does my vise grip...the jaws are modified a little though...to make the pressure surface a little broader. (I hope the pic with the rubber bands on both my nuts isn't too dark.)
The rubber bands are lobster claw bands, the ones that the fishmonger puts on the claws of lobsters so they don't bite the hand that eats them.
The Geezer