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/ejector Packages 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.