Football Match Ball And Number Of Players

Match ball
The match ball should be round, and the outer shell of the ball should be made of leather or other permitted materials. The International Football Association Board shall decide the material of the ball at any time. Any permitted material shall be approved by the International Football Association Board. Materials that may harm athletes shall not be used in the structure of the ball.
The circumference of the ball shall not be more than 71 cm or less than 68 cm. The weight of the ball shall not be more than 453 grams or less than 396 grams at the beginning of the game. After inflation, its pressure should be equal to 0.6-1.1 atmospheric pressure (at sea level), which is equivalent to 600-1100 g/cm2. During the game, the match ball shall not be replaced without the referee's permission.
Number requirements
1. There shall be no more than 11 players on the field of each team (including 1 goalkeeper). The game cannot be played if there are less than 7 players.
2. Players shall be replaced according to the prescribed number, but the replaced players shall not participate in the game again.
3. Players who are penalized and ordered to leave the field cannot be replaced by substitutes.