RAPID HEATING: Faster warming by seconds, the heater material is explosion-proof quartz glass, and nickel-chromium heating wire materials has higher thermal energy efficiency, and then conducts heat through silicon carbide material, is safer and more durable to use. High temperature resistant plastic cover, not easy to deform, and has very strong corrosion resistance FREQUENCY ENERGY-SAVING: Auto reduces power when approaching the set tempe, by heated at 10% to 30% power, fully utilizes thermal energy inertia to smoothly reach the set tempe, saving energy. The external controller is easy to operation, every press changes the set tempe by 1℉, ranges from 59℉(15℃) to a max of 93℉(34℃) in order to meet your needs INTELLIGENT THERMOSTAT: Over-temperature protection prevents "cooking fish". When the water temp exceeds about 95 °F, flashing 95 number code, red and green light flash together; and over 93℉, the heater will stop heating automatically. When the water temp cool down to below 93℉, the heater will start working auto ANTI-DRY PROTECTION: Intelligent temp sensing, when the heater is exposed to air, display ER fault code and the heater will shut off automatically. When the heating rod is completely immersed in water, it will start working automatically. Effectively extend the service life. It has a power-off memory function and no need to set it again STRONG SAFETY PERFORMANCE: Build-in intelligent LED digital temperature display. Built-in three temperature probe, real-time monitoring of water temperature, temperature accuracy of 1 °F. Strong suction cup bracket, can stably fix the heater in every corner of the fish tank. Suitable for freshwater and saltwater Fully submersible: The heater is fully submersible. Please note, The heater should be fully submerged to work properly Rapid thermal accumulation: The heating rod is made of explosion-proof quartz glass material and a high-temperature resistant nickel-chromium heating wire with silicon carbide heat conduction; which result in faster water heating and a safer, more durable, long-lasting heater. Build-in intelligent LED digital temperature display: LED digital display screen shows the current and preset water temperature. The external hand controller makes for easy setting and operation. Every press changes the set temperature by 1℉. The led flashes 5 seconds and then stops, indicating that the temperature has been set and the display shows the current temperature.