Allstar 18 inch Diameter 5/8 inch Pilot Hole Steel Mechanical Type Radiator Fan with 6-Blade features a radiator fan that has an 18 inch diameter and is a mechanical type with 6-blades. The fan has a universal bolt pattern with a 5/8 inch pilot hole and is constructed from quality steel material. The fan has a 27 degree blade pitch and can move the great volume of air needed to keep the race engines cool. It is backed by a 90-day limited factory warranty and is sold individually.