A baseball cap is a type of soft cap with a long, stiff brim that may either be curved or flat. The back of the cap may have a plastic, Velcro, or elastic adjuster so that it can be quickly adjusted to fit different wearers. The baseball cap is a part of the traditional uniform for baseball players, worn with the brim pointing forward to shield the eyes from the sun.
Fitted baseball caps, those without an adjuster, are normally sewn in six sections, and may be topped with a matching fabric-covered button on the crown. Metal grommets or fabric eyelets are often sewn or attached near the top of each of the six sections of fabric to provide ventilation. In some cases, the rear sections of the crown are made of net-like mesh material for extra ventilation.
Used mostly with the utility uniform and coveralls, the baseball cap usually has a command logo on the front to denote command affiliation. Also baseball caps of a particular color are worn to denote a specific function of a person or particular job. Two examples are in the United States submarine force, red baseball hats are worn by drill monitors who facilitate and critique members of the boat's crew during drills. Also in the United States Army, parachute riggers wear red baseball caps and parachute instructors wear black baseball caps as part of their uniform.
Baseball caps can be a fashion statement when decorated with embroidery, felt applique, patches, metal eyelets, sequins and so on. Baseball caps provide inadequate protection from solar UV radiation which is known to cause skin cancer. A typical baseball cap leaves the sides of the face, ears and neck all exposed to the full sun light. For serious sun protection, a hat with a broad brim or one with a flap covering the neck and sides of face (often called a legionnaire's hat) should be worn.