Rule 1 – Section 4 – Article 5 – Jersey Design, Colour and Numerals

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c. Numerals

1. The jersey must have clearly visible, permanent Arabic numerals measuring at least 8 and 10 inches in height front and back, respectively. The number must be of a colour that itself is clearly in distinct contrast with the colour of the jersey, irrespective of any border around the number.
2. Teams wearing jerseys/numerals that do not conform to this rule will be asked to change into legal jerseys before the game and before the start of each quarter until the jerseys are changed.

PENALTY − Officials shall charge a team timeout (or a delay penalty if all timeouts have been used) at the start of each quarter the illegal jerseys are worn. (A.R. 1-4-5:I) [S23: IJY]

3. All players of a team shall have the same colour and style numbers front and back. The individual bars must be approximately 1½ inches wide. Numbers on any part of the uniform shall correspond with the mandatory front and back jersey numbers.