Koyorad N-Flo Dual Pass Aluminium Racing RadiatorWhen factory equipped radiators have inlet and outlet locations that allow proper placement, Koyorad carefully welds aluminum partitions in the upper and lower tanks of the radiator. This is Koyorads N Flo Technology which allows for a double or triple pass radiator. This design cools more efficiently by allowing the coolant to remain in the radiator for a longer period of time therefore transferring more heat to the surrounding air. N Flo Technology