Turn any firearm into a safe training option. Barrelbloks are a dry-fire training aid with an easy-to-see safety indicator! BarrelBlok is caliber-specific, making sure your firearm is unable to chamber a round when inserted. They are fully functional – no more training scars! Your slide will function just like it would if your firearm had ammo in it. The rear of the BarrelBlok even has a firing pen strike face, which helps to reduce mechanical vibrations while dry-firing!