High-end Refrigeration Module -- This thermoelectric cooler uses high-end refrigeration module which has high power and good durability ^^ Large Cooling Area -- Cooling block has large area that can more water for quick cooling ^^ Copper Pipes -- Four hollow copper pipes with refrigerant inside would deliver heat fast for higher cooling efficiency ^^ For Fish -- 120W is suitable for 30L fish and 180W is suitable for 40L fish ^^ Energy Saving -- It is energy saving and beneficial to the growth and reproduction of ornamental fish