All Torrid Marine Water Heaters have been redesigned with NEW high efficiency coolant heat exchangers. Previously only available to expedition yacht builders, the Explorer Series have two internal heat exchangers with the option of one or two independent electrical heating elements. Connect one heat exchanger to the engine and the other to a generator or diesel furnace. The two heating elements allows for different power configurations depending on your needs - one for shore power, the other for a generator, inverter or solar power. Explore the possibilities.