Mine is Summits heavu duty stainless.I believe its 17 or 18 inch.It cools my 12.5 440 and on the street or strip it still runs 180 or so and the rad is untouched 65.Its running 12.5 domes also so its not a mild motor.I dont trust the glass fans just my opinion.The one I had on my jeep was 10 years old and all street driver and plow truck.Rocky