The B&B Pro Circuit Breaker/Relay panel is designed to work with two electric cooling fans. Cooling fans pull a lot of power, especially when they first turn on. Install a panel that will handle double trouble from twin cooling fans. 40 amp relays keep full power to the electric fans while twin 30 amp Circuit Breakers monitor and protect the circuitry. One of our popular relay panels for Hotrods, Trucks, and Pulling Tractors! Grounding terminal also located on the panel for the relays.