A pool table varies in many different sizes and can come with different sized balls such as American pool balls which are 60mm and BlackBall pool balls which are 55mm. A billiard table or billiards table is a bounded table on which billiards-type games (cue sports) are played. In the modern era, all billiards tables (whether for carom billiards, pool or snooker) provide a flat surface usually made of quarried slate, that is covered with cloth and surrounded by vulcanized rubber cushions, with the whole elevated above the floor. An obsolete term is billiard board, used in the 16th and 17th centuries.