Where did that ball go?!! If you lost a billiard ball, we can help! The quality of these balls (A grade) are probably much higher than that which came with your table. The balls measure 2-1/4″ in diameter, which is the standard billiard ball size. They are regulation weight. However, note that different ball sets sometimes use different type faces and sizes, so a replacement ball may not look exactly like the rest of your balls. However, it is unlikely that the subtle difference would ever be noticed.