Ed Brown Products Flat Wire Recoil Springs Stainless 4.25in Commander 9mm 15lb. Manufactured from Chrome Silicon alloy to maximize spring longevity and load. The longest lasting handgun recoil spring made up to ten times greater service life than a conventional coil spring. Other benefits of switching from conventional round wire to flatwire include improved cycling and more tolerant to a wider variety of loads. Intended for use with our flat wire guide rod system. Recommended spring replacement at 30000-40000 rounds. Specifications for Ed Brown Products Flat Wire Recoil Springs: Manufacturer: Ed Brown Products Color: Silver Fabric/Material: Stainless Steel Gun Make: 1911 Platform Package Contents: Ed Brown Products Flat Wire Recoil Springs What firearm models does the manufacturer say Ed Brown Products Flat Wire Recoil Springs is compatible with? The manufacturer suggests that Ed Brown Products Flat Wire Recoil Springs is compatible with 1911 Government 5in 1911 Commander 4.25inEd Brown Products 915-FW-9C: Flat Wire Recoil Springs Stainless 4.25in Commander 9mm 15lb