After your Desert Eagle racks up a few miles, install new springs and restore the zing. Recommended every 1,000 rounds for .50 AE (Mark VII & XIX) or every two-three years depending on usage since springs over time with or without use can weaken. Spring tune-up kit includes two outer recoil springs, two inner recoil springs, two retaining rings, ejector pin, ejector spring, magazine spring, extractor pin, extractor spring and firing pin spring. Please note the coil extractor spring has had an inline factory change, the new polymer extractor spring (cone-shaped polymer material) replaces the coil style spring.