The front of the cap typically displays a design or a logo (historically, usually only a sports team, namely a baseball team, or names of relevant companies, when used as a commercial marketing technique). The cap may be "fitted" to the wearer's head or the back may have elastic, a plastic prong-in-a-hole (multiple holes with one prong that can be inserted), Velcro, a zipper, or a tri-glide slide so that it can be quickly adjusted to fit different wearers' heads. The baseball cap is a part of the traditional baseball uniform worn by players, with the brim pointing forward to shield the eyes from the sun. Since the 1980s, varieties of the hat have become prevalent in the United States and many other nations, both for utilitarian (protecting the eyes from the sun) and fashion accessory purposes.