Manufactured from Chrome Silicon alloy to maximize spring longevity and load. This spring offers the ability to replace worn out factory parts and improve cycling in Beretta 92 Compact and Centurion models. Notes:Recoil springs fit over a pistol's guide rod and control how the pistol's slide functions. In general, heavy loads need heavy springs and lighter loads need lighter springs. There is no hard and fast rule as to how much "spring" a pistol needs. Too light a spring and the pistol opens and closes early and hard, increasing felt recoil and battering the frame. Too heavy a spring and the slide is hard to open and may not cycle completely, jamming the pistol.