<b>Hygger digital quartz aquarium heater is specially designed for medium fish tank use, fast heating up for 15-30gallon 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>Main 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 you set it to the digit<br>you want, stop and wait the led flashing for 3 times, then the setting is done and 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, 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 it will automatically turn normal 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> Power: 200W<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> Heater tube length: 10.5 inch<br> Temp control range: 61-90℉<br> Temp accuracy: ±1℉<br> Suggest for fish tank: 15-30 gallon