The Marina Betta Heater is an automatic, submersible water heater that creates ideal water conditions for bettas to thrive in. The exterior is made of durable polymer, which is more resilient than traditional glass sleeve heaters. The fish aquarium heater is designed to reach and maintain a set temperature for your aquarium water; no manual adjustments required. It has a red indicator light that illuminates when the heater is working. It comes with a suction cup, so you can easily install it against the aquarium window. For more fish tank accessories check out the other Marina products including aquarium filters, filter media, aquarium heaters, aquarium air pumps, aquarium lights, aquarium thermometer, aquarium gravel, aquarium decorations, betta fish accessories, betta fish food, aquatic fake plants, betta tanks, and aquarium stands. Marina has a wide variety of products that are perfect for your pet fish or betta fish to enjoy in any large fish tank, small fish tank, freshwater tank or a saltwater tank.