<b>About intelligent indicator green light and red light:</b><br> Press set button to start the temperature setting. The LED display will start to flash, continue pressing set button, until it reach your desired temp. When the water temperature is below your set range, heating function of red light will engage and increase temperature automatically, while green light means the water temperature is within desired set range and monitoring function is engaged.<br> <br> <b>Please read carefully about the following tips:</b><br> 1.DO NOT use the aquarium heater if the cord / heater is damaged.<br> 2.You MUST NOT place the controller in the water.<br> 3.Please cut off the electricity when installs the heater.<br> 4.Please unplug the heater when cleaning the fish tank or changing aquarium water.<br> 5.Children or minors should be under adult guidance or supervision.<br> <br> <b>Item Specification:</b><br> Power & Voltage: 100W & 110V~120V (The power cord and plug have UL certification)<br> Capacity of Tank: 5 to 26 gallons<br> Outer Temp Control: Ranger from 68℉-93℉(±1℉)<br> Length of Cord: 59 Inches from controller to heater, 39 inches from controller to plug.<br> <br> <b>Includes Package:</b><br> 1 x 100W Heater with 2 Suckers Attached & 1 Temp Probe<br> 1 x External Temp Controller<br> 1 x Installation Manual<br>