A baseball uniform is a type of uniform worn by baseball players. Most baseball uniforms have the names and uniform numbers of players who wear them, usually on the backs of the uniforms to distinguish players from one other. Baseball shirts (jerseys), pants, shoes, socks, caps, and gloves are parts of baseball uniforms. Most uniforms have different logos and colors to aid players, officials, and spectators in distinguishing the two teams from each other and the officials. They are made out of polyester instead of cotton as washing shrinks the cotton fabric.