<b>Hygger mini quartz glass aquarium heater is specially designed for small and medium size tank use.<br></b>This fish tank heater is very safe and durable, milky quartz material made, can resist a high temp of 1800℉, <br>excellent in explosion-proof & shatter-resistant.<br>The service life can be more than 3 years if only using in fresh water.<br><br><b>There is a led indicator light on the temp controller.</b><br>When the tank heater is heating, the indicator light is red. When it stops heating, the light is off.<br><br><b>When does the heater stop and restart heating?</b><br> The aquarium heater is very reliable to maintain the water temp as your set. It will stop heating when the water <br>temp reaches to<br>the set temp and will restart heating when the temp is 1.5-2℉ below the set temp.<br><br><b>Over heat protection</b><br>The aquarium heater will auto shut off once the water temp is over 97℉.<br><b>How to adjust the temp?<br></b> Rotate the knob on temp controller to set it to the desired temp. Temp range is 68-90℉.<br><br><br><b>Size Chart</b><br>Power & Tank: 50W (5-15gallon） 100W (10-30gallon)<br>Heater Length: 5inch 7inch <br> If the room temp is lower than 50℉, please buy a larger wattage heater.<br><br><b>Do’s and Don’t’s<br></b>1. For better experience and aquarium safety, please carefully read and follow the user manual.<br>2. Keep the aquarium heater fully submerged in water.<br>3. Stick the heater horizontally or vertically onto the tank side near the water intake or on the way of water flow. <br>4. Don’t bury the heating rod in sand or stones.<br>5. Please keep the temp controller away from water.<br>6. Please don't connect the power before the heater is well installed.<br>7. Please wait the heater rod to cool down before you move the heater or change the water.<br><br><b>Specification:</b><br> Voltage: 110-120V <br>Frequency: 60HZ <br>Cable Length: 4.6ft<br><br><b>Package Includes:</b><br>1 Aquarium Heater<br> 1 User Manual