Most modern footballs consist of twelve regular pentagonal and twenty regular hexagonal panels positioned in a truncated icosahedron spherical geometry.[Some premium-grade 32-panel balls use non-regular polygons to give a closer approximation to spherical. The inside of the football is made up of a latex bladder which enables the football to be pressurized. The ball's panel pairs are stitched along the edge; this procedure can either be performed manually or with a machine.[3] The size of a soccer ball is roughly 22 cm (8.65 inches) in diameter for a regulation size 5 ball. Rules state that a size 5 ball must be 68 to 70 cm in circumference. Averaging that to 69 cm and then dividing by p gives about 22 cm for a diameter. The ball's weight must be in the range of 410 to 450 grams (14 to 16 oz) and inflated to a pressure of between 0.6 and 1.1 bars (8.5 and 15.6 psi) at sea level.[9] There are a number of different types of football balls depending on the match and turf including: training footballs, match footballs, professional match footballs, beach footballs, street footballs, indoor footballs, turf balls, futsal footballs and mini/skills footballs.
