4500w, 240v, water heater screw in fold back element, 50w per sqin, minimum tank diameter 15", gasket included, fits most models of American, a.o.smith, Bradford white, craftmaster, general electric, gs wood, Kenmore, lochinvar, Maytag, mor-flo, reliance, rheem, Richmond, ruud, sears, state, & whirlpool heaters, best when water has high mineral content, withstands dry firing, heats in lime & sand build up that would burn out ordinary elements, highest grade nickel & chromium incoloy, ultra low watt density, ul listed, limited life time warranty.