Only size 5, and size 4 are available for this. Although this should not be a major problem as this is for recreational play and practicing purpose, so kids are ok to play with this as well. In fact, the ball that will be given away to the developing countries will be used by the kids mostly. If you are buying this for an adult go for size 5, and if you are buying for kids or youth players then better go for size 4.
Adidas spared little expense with this soccer ball and made sure that the materials used could pass almost any standard for grass fields. First, the casing is made of polyurethane, providing a great balance between responsiveness and durability-though they further increased the responsiveness with 3D textures. The bladder is made out of butyl, so you will not have to worry about constantly reinflating it, while the ball is lined with soft and water-resistant polyester.
If you've ever noticed, a traditional soccer ball resembles a geodesic dome building. Such as the one designed by architect, Richard Buckminster Fuller. Thus the ball became called the Buckminster Ball. Or more simply, the "Buckeyball". The design is characterized by a pattern of twenty hexagon pieces, and twelve pentagon pieces, fitted together to create a perfect sphere. The soccer ball has undergone many design changes of various-shaped panels stitched together. But until the geodesic dome-like ball, it was never quite round enough to perform right. Manufacturers settled upon the modern thirty-two panel design, which enables the ball to roll and spin more evenly and smoothly. Which is probably why it's the most popular competition soccer ball on the market today. The Buckminister-style soccer ball was first sold in the 1950s, and debuted in the 1970 World Cup tournament.
Latex bladders are one of the best materials when it comes to ball construction. However, with latex bladders, air won’t last as long as butyl bladders and will need more attention for proper inflation. Butyl-blend bladders hold in the air much better, but they are harder and less receptive in play. Mid-priced balls will usually have a mix of butyl and rubber. https://www.youtube.com/watch?v=c1SVcjYY6TE