These are spent casings. Meaning that at one time it was a complete bullet and since then has been fired. Leaving the spent casing behind. This is important. You want to make sure you are using spent casing in your crafting. The sure fire way to tell if the casing is not "live", is to make sure there is a dimple in the very center of the shell casing, where the letters are. (see picture)
Sold in packs of 5, 10, 20, & 50 The pictured bracelet is for reference only.