Let me jump into the hot water and tell you that you can save yourself all the trouble of buying the hot water urn in Israel and shlepping it all the way to the USA. While you are here, you can walk in to any store that sells electrical appliances in Boro Park. Flatbush, Williamsburg or Monsey and purchase just such an urn. No special switches are needed since those urns have two settings. “Boil” and “keep Warm”, which is a default setting from the factory.
p.s.: Poster Zach Kessin, was right on point with the advice that the voltage and frequency (Hz.) of any electrical appliance must be compatible to the power source, rather than the plug.