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.