The Woliver Aquarium Heater is a small, submersible heater that is perfect for keeping your marine or freshwater aquarium warm. With a digital temperature control system, it is easy to keep the water at the perfect temperature. The heater is made of thick quartz for durability and resistance to shattering. The power cord is 4.3 feet long and the water temperature range is 64 degrees to 93 degrees Fahrenheit.