All aluminum front suspension system for 1964.5 -1970 Mustangs featuring Detroit Speed's unique suspension geometry with 6" of suspension travel for the ultimate in ride and performance. Spring Rate: 400lbs/in Spring Free Length: 10inSingle Adjustable Shock: Includes all features of base shock with 'Detroit Tuned' valving plus installed rebound adjustment with the simple turn of a knob while providing excellent ride quality on the street.