Size 4 footballs are used for 7-a-side football by under 10s, 9v9 for under 11s and 12s and junior 11-a-side football for under 13s and 14s. The correct size ball for these age groups is really important for your younger players development. Our size 4 match balls are quality footballs and will help these superstars in the making get to grips with the game quicker and be more equipped when it comes to a full size football.