Size and weight standards for size 5 football:
Perimeter: between 68.5 centimeters and 69.5 centimeters.
Weight: between 410 grams and 440 grams.
Pressure: 0.6 to 1.1 atmospheres (600-1100 g/cm2).
Material: 3.5mm PU thermal bonding+fabric technology
Standard football performance:
Durability: After withstanding 2000 impacts at a speed of 50 kilometers per hour, the shape and size of the football should remain stable.
Rebound performance: When falling from a specific height, the rebound height should be within a certain range and not exceed 10 centimeters.
Water absorption: After soaking in water, the weight of a football does not increase by more than 10%.