Amazon.com: Whale S360EW 12V Water Heater, 3 Gallon Capacity, Quick and Efficient Water Heating, Maintains Hot Water up to 10 Hours, Runs on 12V DC Power, Ideal for Use with Deck Showers, :
Bosch Tronic 4000C 240-Volt 8.5-kW-kW 1.65-GPM Point Of Use Tankless Electric Water Heater in the Tankless Electric Water Heaters department at Lowes.com