Over heating heaters is a hobbyist nightmare. To protect your aquarium investment and live stock, this heater controller is a must. The digital controller maintains your heater within a safe temperature providing a healthy and stable temperature for your aquarium. Automatic shut off over heat protection will cease the heating process. A temperature probe is included to ensure a more accurate aquarium temperature reading. The three prong power receptacle works well with other compatible heating elements equal to or less than 300 Watts. Add a controller for double heating protection! If power is interrupted a memory chip is incorporated to resume users preset temperature once power resumes. *Not compatible with Aqueon PRO* heater series. Finnex HC810M or HC800 controller recommended for such. *Do not use with defective heating tubes. Defective heater tubes may be drawing excess watts and in turn make the MAX 300 controller fail.