Mikasa Soccer Size Japan Football Association Approved Ball Elementary School Recommended Internal (MIKASA) Ball, 4, (for Students), Hand-stitched,

Official ball of the Japan Football Association No. 4 ball (for elementary school students) Artificial leather / Hand-stitched Diameter approximately 21 cm, circumference approximately 63.5-66 cm, weight approximately 350-390 g, recommended internal pressure 0.61-0.81 kgf/cm²