Submersible Heater is an advanced-compact design, double sealed submersible aquarium heater. The Visi-Therm features a water calibrated thermostat is certified accurate to within one degree, ensuring precise temperature selection and superior performance. It also delivers the ultimate in direct-set control, with a simple "click" of the dial; you choose the ideal water temperature. Meanwhile, its durable design is held to exacting standards for accuracy, extended submersion and operational safety. Only at Dog 360.