It's called a hone, "flex hone" by most in the industry but also carries the "ball hone" name for about as long because of how it looks, it just makes you want to say "ball hone" and that quickly differentiates between the styles of hones so you know what the other guy is referring to.
It will remove material of you hone or "scratch" with it long enough...lol jk @toolmanmike , just like a scratch removes skin from your arm.