Footballs should be inflated to an air pressure of 13 pounds per square inch, according to the NFL rules. Official footballs, which are manufactured at the Wilson company facilities in Ohio, weigh between 14 to 15 ounces.
Official game footballs used in American collegiate and professional leagues are made with cowhide leather. About 10 footballs can be made out of a single piece of cowhide. The football has four leather panels that are tanned to a natural brown color, which is the requirement in collegiate and professional football games. The tanning process, as well as the pebble grain texture, helps players have a better grip on the ball.
In the NFL, the home team is required to have 36 balls for an outdoor game and 24 for an indoor game. The balls are to be made available for the officials before the came for inspection and to test with a pressure gauge 2 hours before the game.
The game also requires 12 kicker balls that are sealed in boxes with special anti-tampering tape be delivered to the officials' locker room 2.5 hours before the game for inspection. The difference between kicker balls and the game football is that the kicker balls are marked with the letter "K." The inspections are made to ensure that the balls are not tampered with and are used especially for the kicking game.