The Fins First 150W Submersible Aquarium Heater is designed for 40-gallon tanks, making it suitable for a wide range of water types including fresh and saltwater. This heater, made by the brand Fins First and manufactured in China, is a reliable and efficient choice for maintaining the temperature of your aquarium. Each unit is sold individually and is ideal for pet owners looking to provide a comfortable and consistent environment for their fish and aquatic animals.