To build a tad on Cletis' answer. It's the current (amps) that decided whether a switch is happy or not. A 6v system actually uses double the current of a 12v system so your switch should live happily every after on 12v.

Save a life, adopt a senior shelter pet.
The three main causes of blindness: Cataracts, Politics, Religion.
Name your dog Naked so you can walk Naked in the park.