ISMI premium springs are manufactured exclusively with certified aerospace specification alloys; stainless or chrome silicon. Then our springs are heat treated, shot peened and stress relieved after winding to enhance performance and durability. Our springs utilize the same design and manufacturing technology as used in IndyCar and Formula One racing. In a typical 500 mile race, a valve spring in an IndyCar will go through more than 2,500,000 compression cycles. Consideration of factors such as modulus, wire diameter, mean diameter, active coils, total deflection, spring relaxation, maximum service temperature, and operating environment; results in you having modern spring technology available for your pistol.