In gridiron football, the face mask is the part of the helmet that directly covers the face. It is a major protection for the players, made of metal covered either with rubber or plastic. Details of the face mask may vary according to each player and their needs. For example, the quarterback's face mask in previous years could be just a single horizontal bar, since he has a need to see the entire field. (Single-bar face masks are no longer allowed in most levels, except for players who began using the single bar before the rules were implemented.) Positions such as linemen, however, may have several bars on their face mask, both horizontal and vertical.