The TropiCal® is an economy heat pump designed to fit any budget. It is perfect for above-ground pools and small in-ground pools. Optimum heat output in a small footprint Large surface and corrosion resistant evaporator Vinyl coated fan grill Microprocessor controlled automatic defrost allows operation down to the mid to lower 40s High performance titanium heat exchanger (patentedThermoLink® heat exchanger in the T115 and T135 models)