Cold wound, not hot wound. Each coil-over spring is properly heat treated and stress relieved to insure the sides of spring remain parallel during installation, Powder coated, not plated to protect the spring from hydrogen embrittlement, a corrosive break down of the spring's surface which decreases the spring's life, Each spring is designed with the correct pitch and height ratio to insure consistent rate throughout the entire cycle., Closed and ground on both ends which insures proper contact with the jack plate and spring seat, Made of the highest grade of Chrome Silicon wire found worldwide.