This is 12 gauge ammo loaded with Flechette darts. A Flechette is a small dart shaped projectile, which have fins and is made from steel. This unique application of loading these Flechette darts into 12 gauge shells was widely used in Vietnam for taking out snipers hiding in thick cover and trees. Due to the penetration of these projectiles, tree limbs and brush would not disperse the darts. Even if some were dispersed, this would still have an all-covering pattern within a tree or brush. This ammo is effective in thick cover. Generally 25 to 30 of these darts are placed in each 12 GA. shell.