Allows the removal of the thermostat. Can be used with most electric pumps, removing the impeller mechanical pump. Controller operates electric water pump and fans based on coolant temperature. Cycles the pump during warm up to keep hot spots in the heads from forming. With no thermostat in place reduces the possibility of leaks due to pump pressure. Pretty awesome particularly for SBC Conversions.

http://www.streetlegaltv.com/tech-stories/...y-davies-craig/

http://daviescraig.com.au/

I wonder if I could use the current fans I have, instead of changing that part?

Neat and I'm sure it has it's application but one point is obviously overlooked with their broad blanket statement:
Since it relies on engine RPM to circulate coolant the engine driven water pump operates counter to what demand typically dictates. At idle when there’s no air being forced across the radiator by the vehicle in motion the water pump is also circulating extremely slow leading to heat soak and higher engine temperatures. At speed when airflow helps tremendously with cooling, the pump is often moving more coolant than it needs to. “A mechanical pump can’t be designed to operate efficiently or ideally under all circumstances,” says 3P Connect’s Josh Backes.
This is also the time when internal combustion engines are producing the most BTU!