<p><b>How to use the temp setting?</b></p><p>Press the button on the controller over and over, the set temp digits will go circularly from 63℉ to 94℉, when you set it to the digit you want, stop and wait the led flashing for 4 times, then the setting is done and the led will go on displaying the water temp.</p><p></p><p><b><br></b></p><p><b>Heating indicator light</b></p><p></p><p>There are 2 indicator lights below the display screen, the left light will on red when the submersible aquarium heater, is heating, the right light will on green when it stops heating.</p><p></p><p>Electronic temperature control heater</p><p><br></p><p></p><p><b>Specifications:</b></p><p></p><p>Voltage:110 V-120V Frequency: 50HZ</p><p></p><p>Led Indicator Light:When it working, the indicator light is red.</p><p></p><p>Temperature Range: 63℉ to 94℉ Temp exactness:±1℉</p><p><br></p><p></p><p><b>Aquarium Heater Submersible:</b></p><p></p><p>Double-loop circuit design, the water temperature sensor is installed in the IC circuit to prevent air burning and heating over temperature.</p><p></p><p>Temperature control is accurate adjustable.</p>