The Reef Octopus USB Smart Fan automatically adjusts its speed based on the ambient temperature around the thermostat. Its an ideal solution for aquarium canopies, enclosed stands, and equipment cabinets, helping to regulate the temperature in these spaces. Maintaining cooler conditions in these areas reduces heat transfer to the aquarium, preventing dangerous temperature spikes and enhancing the longevity of your equipment. The fan speed increases at 90F and continues to ramp up to its maximum CFM at full speed by 110F.