The most common object ball diameters are and . Balls pocketed via combinations off of the object ball are legal. The shooter may attempt to shoot at any object ball on the table. An object ball not pocketed is left on the table. One point is scored for each object ball pocketed where no is made. A player can shoot at and pocket any object ball on the table. Nobody gets a letter if the object ball goes in a pocket on a serve. Scratches on any object ball allow the opponent ball-in-hand, but the sunk ball remains potted. No player may intentionally knock the object ball back into play (penalty is a life).