Balls were a popular game for elementary school kids when I was little, and such ball bearings were considered all-around bad. we called them "steel". The fact that they could sometimes shatter or shatter ordinary glass marbles only added to their mystique. Ah, what innocence by today's standards. Well I ordered them thinking I could use them as electrical charge carriers in an experimental static electricity generator for my kids. Logically, a spherical shape would work best for this, so why not?