IceCap Variable Speed Cooling Fan
This nearly silent, tiny 4-3/4" fan is specifically designed for harsh saltwater environments. Equipped with an 18-inch probe that senses the air temperature inside your hood and adjusts the fan's speed accordingly. 50-102 CFM. It will run at the 50 all the time and if it get hot it will go faster…
I don’t know if that is what you are looking for.
I have two on my 120g and 4 on my 210g they work grate