Cue sports playing nine-ball. Snooker balls are smaller than American-style pool balls with a diameter of 52.5 mm ( in), and come in sets of 22 (15 reds, 6 "", and a cue ball). English billiard balls are the same size as snooker balls and come in sets of three balls (two cue balls and a red, an object ball). Other games, such as bumper pool, have custom ball sets. Billiard balls have been made from many different materials since the start of the game, including clay, bakelite, celluloid, crystallite, ivory, plastic, steel and wood. The dominant material from 1627 until the
History of snooker competitions in total that were open to most professionals. Those players lower down the rankings required second jobs to supplement their income as the game for them had become a part time choir. In contrast, the provisional calendar for the 2011/2012 season features 9 ranking tournaments, 13 minor ranking events under the Players Tour Championship brand and 7 invitationals which include the traditional Wembley Masters and the shot clock Premier League. The calendar increasing to a record breaking 29 official World Snooker events. The sport is now a full time profession once again. Format alterations such as Power Snooker and