If you're looking to update or maintain your EDC X9 or SFX9 handgun models, this spring is the perfect choice. Their flat wire recoil spring is covered with a chrome silicon coating that offers superior corrosion and abrasion resistance.Chrome silicon coated flat wire spring for increased service life13 lb rated spring for 9mm caliber firearmsWorks exclusively with the EDC X9, SFX9 4", and Experior compact double stack 4" modelsAverage service life of 40,000 roundsRecommended Use: Wilson Combat EDC X9 4" 9mm with reduced power target or full charge self-defense ammunition with a power factor of 125,000 to 150,000 ( Velocity x Bullet Weight = Power Factor )