Chrome silicon steel recoil spring resists taking a set even after thousands of compression cycles for improved performance and reliability. Available in three power ratings, so you can match spring weight to your specific gun and the type of load you shoot. Use Reduced Power 14 lb. spring for target loads with lighter than standard bullets or powder charges, Factory Standard 16 lb. spring for all-around reliability with the widest range of ammo, and Extra Power 18½ lb. spring for smoother cycling and less slide battering with heavy loads. The 14# and 18 1/2# springs comes with an extra power firing pin spring to ensure positive ignition and an extra margin of safety in preventing accidental discharges.