This is the standard 8V regulator that is used to be able to run any 12V fan off of a voltage source (such as a power supply) under 35V.
This works with most 12V fans. This regulator is preset to run at 8.0V with no additional components required, just plug it into the main power supply (10-35VDC) and it will output a very consistent 8.0V. The reason why we don't use a 10V-12V output is because the fan moves about 80% of the air, but is more than 6 times more quiet.