Ultimate-match coil shock springs for pancars and formula front suspension offer an additional range of choices to fine-tune your car. Powder color-coded for quick & easy identification. Grey color. C=3.0 (soft). Set of 2. Developed through extensive testing and racing experience. Stiffness is controlled by the thickness of the wire and the number of coils; softer springs have a lower "C" value, stiffer springs have a higher "C" value.