With the Eheim thermocontrol-e heating rod, your fish will experience the perfect temperature with even greater precision in any aquarium. While the principle is still the same as it was decades ago, the Eheim controller heater has now become a state-of-the-art thermal device. The temperature can be set precisely and is measured and maintained even more accurately by the electronics. The special laboratory glass casing increases the heating surface, acts as a heat shield, and ensures even heat distribution. Whether you want to heat a 20 or a 1200-liter aquarium, you can choose from 10 different sizes. Precise temperature setting from 20 to 32 °C.