Features extra large 1? tubes for 4 row efficiency but with 5-7 lbs. less weight. We also added Scott Drake exclusive baffle at the top to help evenly distribute the flow of hot water across the upper part of the radiator. The original radiators had a real problem distributing the hot water to the far right side of the radiator. We have tested Drake's design and recorded significant changes in the temperatures across the radiators cooling tubes. A/T cooler included.