Electro Polished Pro - Alloy 1.550 Dual Valve Springs We took our state-of-the-art Pro-Alloy roller valve springs one step further. Each of these springs are electro polished, which enhances the material even further. By reducing localized stress areas, these springs offer even greater life expectancy. Each spring is coiled using the most advance CNC winders in the industry. Each spring is then parallel ground, stress relieved and deburred. They are then shot-peened and heat-treated to our own very specific standards. These high standards are what it takes for a longer spring life, even in rough racing environments. Unconditionally Guaranteed against breakage for one year! Just return the broken spring and we’ll replace it, no questions asked.