Oase HeatUp Aquarium heaters are a robust and reliable way of controlling the temperature in your tank. The slim design heaters can be easily controlled to enable you to readjust the temperature precisely ( + / - 3 °C) depending on the needs of your tank. The function of the heater can be easily detected by way of the activated control light at the front of the tube. The temperature levels can be controlled and monitored by the patened bi-metal technology runinng through the heater. This technology ensures the heater elements do not fuse in an on position and enables it to keep an accurate check of the temperature for a longer period of time.