Wilson's primary basketball series are the NCAA, Evolution, Solution, and Collegiate. Wilson basketballs are typically constructed of composite leather and butyl bladders. The composite leather surface absorbs sweat from sweating palms, preventing the ball from slipping from the fingers during play. The butyl bladder inside the ball provides much needed cushioning for hands and balls during games. In addition to composite leather and butyl bladders, some models may also include nubuck leather uppers or mesh vents. Nubuck is a natural fiber derived from the neck and chest area of the horse. It has a nice soft feel and looks good too! Mesh vents allow for more air to be pulled into the bladder, which helps it stay inflated longer. The men's basketball comes in sizes 5-9, with weights ranging from 7 ounces to 9 ounces. The women's basketball comes in sizes 4-7, with weights ranging from 6 ounces to 8 ounces. Balls that are too heavy for an individual to lift comfortably are called "overcrowded". Balls that are either too light or too heavy are called "undercrowded" or "oversized", respectively. The size and weight of a basketball will usually be indicated by its "sock" number (also called its "ball size"). There are several different types of socks used in the industry.