The Fluval E Heaters continuously monitor and display aquarium water temperature, ensuring the well-being of your aquarium inhabitants. The E Series features VueTech technology. With the easy to use adjustment lever, the temperature can be precisely set in 0.5 increments. Its LCD display delivers peace of mind by continuously showing real time water temperatures. During normal operation, the temperature readout will change color if the water varies +/-2 degrees F or more from the pre-set temperature. If any external heat sources or other equipment, such as chillers, cause the aquarium water temperature to rise or fall beyond 5.5 F, the colored screen will flash, indicating a potential risk. The ability to measure temperature in Celsius is also an option. The integrated fish guard offers advanced protection. Fish and invertebrates cannot come into direct contact with the heater core. The glass sleeve is also protected against shocks from large fish species. Built with a secure slim profile mounting bracket, it can be adjusted or removed without removing the mounting bracket. For those with a marine aquarium and sump, you can also attach the Fluval E heater there. WARNING: The heater must never be operated outside of the aquarium. If the water level falls below the minimum water level MIN, the thermostat can no longer "read the water temperature and therefore can no longer control the heating correctly. If it has to be taken out of the water or when transferring or changing the water, disconnect the heater from the power source and wait for at least 30 minutes to allow it to cool down. For more fish tank accessories, check out other Fluval products including aquarium filters, aquarium heaters, aquarium air pumps, aquarium lights, aquarium rocks, aquarium thermometers, and aquarium stands. Fluval has a wide variety of products that are perfect for your pet fish to enjoy in any large fish tank, small fish tank, saltwater tank or freshwater tank.