Blackball (pool) number "8" (a holdover from kelly pool), though numberless variants are not unknown. British pool tables come in 6 × 3 foot (1.8 × 0.9 m) or 7 × 3.5 ft (2.12 × 1.06 m) varieties, with 7 feet being the regulation size for league play. The table has pockets just larger than the balls and rounded, as in the game of snooker, whereas the international-style (or "American-style") table has pockets significantly wider, with pointed . Tournament rules may require the presence of more than one type of (mechanical bridge), as in snooker. There are two competing standards bodies that
Billiard table increase difficulty. The amount of (trimmed underside of the rubber cushion's protruding at the pocket opening), if any, has a strong effect on how easily a ball is accepted by the pocket (the ""). On snooker and English billiards tables, the pocket entries are rounded, while pool tables have sharp "". This affects how accurate shots need to be to get into a pocket, and how fast they can be when not dead-on, including shots that run along and against a cushion, making snooker more difficult to play than pool. According to the WPBSA official rule book, "the pocket openings