<b>Hygger 300W digital quartz glass aquarium heater is specially designed for medium and large fish tank use,<br> fast heating up for 30-60gallon aquariums.</b><br>It comes with 1 quartz heater, 1 IC temp controller and 1 thermometer, the cables are all long enough for use indoors.<br><br><b>Other features of submersible heater:</b><br>1. Fast heating and reliable, fully automatic control.<br>2. Black plastic heater guard with suction cups<br>3. For freshwater and saltwater use<br>4. The controller with memory function in case of power-down.<br><br><b>How to use the temp setting?</b><br> Press the button on the controller over and over, the set temp digits will go circularly from 61 to 90, when<br> you set it to the digit you want, stop and wait the led flashing for 3 times, then the setting is done and<br>the led will go on displaying the water temp.<br><br><b>Heating indicator light</b><br> There are 2 indicator lights below the display screen, the left light will on red when the heater is heating,<br>the right light will on green when it stops heating.<br><br><b>Over temperature protection.</b><br>The fish tank heater will auto shut off if water temp is over 97℉, and will automatically turn normal<br> work when water temp is less than 95℉.<br><br><b>Use directions</b><br>1. Keep the heater and thermometer fully submerged.<br>2. Don’t bury the heater under gravels or sands.<br>3. Keep the temp controller away from water.<br>4. Keep water circulation as far as possible.<br>5. Unplug the heater and wait it cool down before doing water changes.<br><br><b>Specification:</b><br>Voltage:110-120V/60HZ<br> Heater tube material: quartz glass<br>Plug: three-pin US plug<br>Power cord: heater cord 6ft，the controller cord 5ft, the thermometer cord 4.6ft<br>Temp control range: 61-90℉<br>Temp accuracy: ±1℉<br> Size: 300W (30-60 gallon), 500W (60-120 gallon)