This device provides a continuous 8V supply to the fan of your choice for a radio-controlled (RC) car, thus guaranteeing constant heat dissipation from the motor throughout the race.
Usually, if you connect your fan to your receiver to power it, it receives a voltage of 6V, lower than the optimal operating voltage of most RC fans. This results in a significant loss of their cooling capacity.
On the other hand, if you plug the RC fan directly into the battery, the voltage drops as the car runs. So when your engine heats up, the cooling power also decreases, which is not an ideal situation.