Choosing the right ball is important for your health and safety, and these guidelines should be adhered to while purchasing basketballs for official or unofficial games.
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Senior (Size #7) is the official size basketball (Circumference 76 - 79 cm, Diameter 24.5 - 25 cm).
Youth - (Size #6) is recommended for women and teenagers (Circumference 69 cm, Diameter 22 cm).
Junior (Size #5) is recommended for small children (Circumference 58 cm, Diameter 18 cm).
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The Men's size 7 regulation basketball has a circumference between 29.5-30 inches, it weighs 20-22 ounces, and has a diameter of 9.39 inches.
The Women's size 6 regulation basketball has a circumference between 28.5 and 28 7/8 inches, it weighs 17.5-19.5 ounces and has a diameter of 9.07 inches.