<p>The temperature of your aquarium is an important factor in the comfort and well-being of your fish. <br>Unlike humans and other mammals, fish do not produce their own body heat. <br>They must rely on the temperature of the water to maintain their body temperature. <br> This makes it very important that you keep your aquarium at the proper temperature for your pets. <br></p> <p> <b> Our High Quality Quartz Glass Submersible Aquarium Heater is here for you! You will get more consistent and efficient heating with it. </b><br></p> <p> <b> Finding the Right Aquarium Heater Size</b> <br> - It’s the totally submersible, it can’t work without submersion, plug the heater in while it was in water, if you change the water for fish tank, power 10 minutes in advance please.<br> - The red light indicates that the heater is working, you should rotate the red botton to adjust the suitable temperature to what you want before put it into the tank (but must be higher than normal water temperature). <br> - The heater should be placed in the water flow and not in a stagnant area.<br> -The heater tube length is important because heat rises. It should match the height of your aquarium. Our Submersible Heater tube length is 12inch. <br> -Using the Aquarium Heater Size Guide, find the size of your aquarium in the left-hand column and move to the column that shows the number of degrees the aquarium needs to be heated. If the heating requirement is between levels, move up to the next larger size. <br> -Heaters should be installed at opposite ends of the aquarium to heat it more evenly. <br> -In larger tanks, or a situation where the room temperature is significantly below the desired water temperature, two heaters may be required. <br></p> Temperature display scale can be set between 20°~34°C(68° F - 93° F).<br> More convenience, there is two easy suction cups to attach to aquarium.<br><br> Package include: <br> 1: 1 Aquarium Heater<br> 2: 2 Suction Cups <br>