The Marina Betta Fish Submersible Heater is a great way to keep your fish tank warm and provide optimal living conditions for your bettas. Made of durable polymer, this heater is tough and will last for years. The easy-to-install design makes it quick and easy to set up, and the automatic reach-out function ensures that the set temperature is always met. With its 8-watt output, this heater provides plenty of warmth for your fish tank.