Now you know that there are total 5 variations in ball size. Buy the appropriate size as per your requirement. Some buyers who don’t know these differences, make a mistake while buying. For example, if someone is looking for an official match ball, but they purchase a size 3 ball by mistake or because of lack of knowledge. If you also do this, surely you are not going to be satisfied with the purchase.
Adidas says its design was motivated by Russia's urban landscapes. It uses textured graphics and a metallic sheen to bring a modern look to the classic design. The ball is made of six panels of thermally bonded TPU and about 15% silicone. The materials allow for better trajectory, accuracy, responsiveness, and low water absorption. It also feels well-padded and slightly lighter than previous match balls.
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