Watch grading guide video, it gives a taste that what balls will look like (it is hard to film wear). All sets can include X-Outs, Practice or Refinished balls, but most of the sets don't have these at all and amount of these balls is very small.
5A - Almost like new balls. Can be very small discoloring, pen mark or a logo. Please notice that these are still used and can be some very little wear.
4A - Good quality balls, which ones have some discoloring, little wear, very little scratch or very little hit mark. Harms on these balls won't affect negatively to your game:)
3A - Playable balls which ones have more wear, scratch(es) or big pen mark.
Practice - Awful balls:)