There are three types of primer pocket tools: profiling reamers, cleaning tools, and uniformers. The reamers are usually shaped to remove crimps and can widen a pocket if used at an angle or roughly. Cleaners usually look like a screwdriver and just scrape carbon off the bottom of the pocket. Uniformers are depth cutters, but typically have no cutting flutes on their sides. They are end cutters only, so they can't widen a pocket, only deepen in.