Carlson's Snap Caps allow for safe release of firing pin springs. A spring loaded striking area cushions and protects firing pins. An excellent tool for teaching and eliminating flinching. Two Snap Caps are included in each package.Features:Prevents damage and prolongs main spring life.Precision machined to true SAAMI specs.Primer material is correct hardness to prevent striker/firing pin over-protrusion.Aluminum won't damage the chamber/extractor/ejectorPackages of 5 snap caps are bare minimum for training with multiple magazines for pistols.Snap Caps are a critical training aid for learning how to fix malfunctions quickly and efficiently not only for competition shooters but for anyone who has a gun for self-defense.