4.1 Bingo balls must be available for inspection by the players before a bingo event begins to determine that all are present and in operating condition.
4.2 Bingo balls must be free from any defects.
4.3 All bingo balls must be equal in size, weight, shape, balance and all other characteristics.
4.4 Each bingo ball must be present in the receptacle before each event begins.
4.5 The numbers or symbols must be clearly indicated on the bingo balls.