unkown voltage for west clocx

Tweet

hi i am trying to figure out what voltage the clock i have it is a automobile dash clock but i dont know what make of car it goes in.ther is a patenten no. on back it reads patented U.S.A. 1848520 1882229 pat. pdg.made by westclox Lasalle. Ill. U.S.A any information on this would be more than i have thank you dave.