This is the replacement cue ball you need for a table using an automatic ball return, where the cue ball is differentiated from the other balls by being slightly larger. Some coin-operated pool tables need this accessory to make the cue ball not get trapped in “billiard ball jail”. It has a slightly larger diameter than a regular cue ball. Sometimes these are referred to as a “mud ball”. If you need a mud cue ball, this is for you! Note that magnetic cue balls are used on Valley pool tables, and not the oversize cue ball.