There are four models of basketball, namely size 7, 6, 5, and 3.
Number 7 is a standard men’s ball, weighing 600-650g and with a circumference of 75-76cm;
Size 6 is a standard women’s ball, weighing 510-550g and with a circumference of 70-71cm;
Number 5 is a youth ball, weighing 470-500g and with a circumference of 69-71cm;
Number 3 is a children’s ball, weighing 300-340g and with a circumference of 56-57cm.