Eibach Coil-over Springs are manufactured from the world’s finest, metric-sized chrome silicon steel wire, available in the smallest incremental sizes IE. .25mm which enable our engineers to produce a superior coil spring. All springs are designed and manufactured to offer the most deflection (travel) available, while offering extremely linear rates as well as the lightest possible weight. Every spring is heat-treated, shot-peened and preset to resist fatigue and are coated with a phosphate and epoxy powder to offer un-compromised durability while offering a great look. All parts are manufactured to be within 2% of the nominal (marked) rate, and are covered under a lifetime guarantee. Available in 2.5" ID to fit any shock absorber with 2.5" perches as well as conventional fronts and rears.