This can be used as a great option for goalkeeper training as well. Why? Look, you can hardly see the lines on this ball, hence you won’t be able to guess the direction by only seeing the spin of the ball. That means as a goalkeeper you will have to give full concentration to detect the direction of the sliding balls. This is obviously helpful if you are a goalkeeper, and looking for a sliding challenge.
This 12-oz. ball works for players between 8 and 12 years old and has a circumference of 26 inches, larger than a size 3 and smaller than the size 5. This age group tends to play on a field of about 30 to 50 yards, writes Deborah W. Crisfield in "The Everything Kids' Soccer Book," with a goal size of around 6 feet high and 18 feet long. Again, the scale for the U12s falls between that of the U8s and that of the older age brackets for the No. 4 ball and the game as a whole. Some leagues may limit the No. 4 ball to U10s instead of U12s, so check league rules before making a purchase.
On the other hand, replicas (sometimes called training balls or gliders) are designed to be just like the official match balls but are much cheaper. Their panels are often stitched rather than thermally-bonded and are made of a different material. However, they’re not necessarily less durable than official match balls. So, they’re the recommended option for most players. https://www.youtube.com/watch?v=j2Xn84L3Kcs