The GMsound Aquarium Heater Submersible Fish Tank Water Heater Thermostat is a high-quality, durable water heater that is perfect for keeping your tropical fish warm and comfortable. With a power of 300 watts, it is one of the most powerful water heaters on the market today. The thermostat features an adjustable temperature range of 65 degrees Fahrenheit to 93 degrees Fahrenheit, and the display is easy to read. The water heater also features two suction cups for attachment to the fish tank, and the polarized plug prevents electrical shock.