Section 2: Equipment

The official NFL football (the "Duke") is made of cowhide leather with a pebble-grain texture. It must conform to the following specifications: Long axis: 11 to 11.25 inches (28–28.6 cm) (Rule 2); Short circumference: 21 to 21.25 inches (53.3–54 cm) (Rule 2); Long circumference: 28 to 28.5 inches...

Source: Rule 2, Rule 5

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