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 100W power rating and a suggested water volume of 15-45 gal, this water heater is perfect for use in freshwater or saltwater aquariums. The thermostat features an adjustable temperature range of 65 F – 93 F (20 C – 34 C) and an on/off indicator light that lets you know when the unit is operating. The water heater also has two suction cups for attachment to the fish tank, and the polarized plug prevents electrical shock.