<b>hygger titanium aquarium heater kits, with 1 digital thermostat controller + 2 suction cups + 1 thermometer.<br> Specially designed for saltwater aquariums, with temp setting remember function.</b><br><br><b>How to set the digital heater temp controller?</b><br>1. When plug in, firstly press the button "Up" to choose the temp unit pattern,℃ or ℉.<br>2. Set the temp: press the button "Set" for 2-3 seconds until the set temp led flickering, then press the<br>button "Down" or button "Up" to set the value to your desired temp, finally, press the "Set" button again to lock the value.<br>3. You can set the temp from 32℉to 104℉.<br><br><b>When does the heater stop and restart heating?</b><br>It will stop heating when the water temp reaches to the set temp, restart heating when the water temp is 1℉ less than the set temp.<br>There is a indicator light on the controller, when the heater is working the light is red, when it stops heating the light is off.<br><br><b>Directions for use</b><br>1. For better experience, please carefully read and follow the user manual.<br>2. Please keep the heater fully submerged in water.<br>3. Place the thermometer away from the heater and keep water in circulation.<br>4. Place the heater horizontally near the water intake or on the way of water flow. <br>5. Please wait the heater tube to cool down before moving it or changing the water. <br>6. Don’t bury the heater in sand or mud.<br>7. Please don't plug in before the heater is well installed.<br> 8. Don't suggest for acrylic or plastic tank.<br>9. Please don’t use the heater alone without the digital temp controller.<br>10. Once the controller occurs fault, please stop using it and contact the seller.<br><br><b>Submersible heater size chart</b><br>Voltage: AC110-120V<br> Wattage & fish tank size: 200W (20-45 gallon), 500W (60-120 gallon)<br> When the weather gets cold and room temp is lower than 50℉, please choose a larger wattage heater than normal recommended.