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.
Face masks first came into vogue in football during the second half of the 1950s, after the hard-shell plastic helmet became commonplace. Single bars were initially the only available design, and this evolved over the course of the next several decades into the current designs, which became the norm at all levels by the early 1980s.
The term "face mask" in the game is also used to refer to the foul of illegally touching the equipment. In most leagues, tackling or otherwise restraining a player by grabbing the face mask is illegal due to the risk of injury, and the penalty is severe, drawing 15 yards, and also a first down if committed by the defense. In high school, the penalty is only 5 yards if the act was considered to be "incidental."
- Cartwright, Lorin; Pitney, William. Fundamentals of Athletic Training. p. 295. http://books.google.com/books?id=19mViFayd7YC&pg=PA295&dq=face+mask+football&hl=en&sa=X&ei=WU8MT9LHNIj40gGzv63OBQ&ved=0CFgQ6AEwBA#v=onepage&q=face%20mask%20football&f=false.
- Sullivan, George. All about Football. http://books.google.com/books?id=wnP6RJ1Pqf4C&pg=PT14&dq=face+mask+football&hl=en&sa=X&ei=WU8MT9LHNIj40gGzv63OBQ&ved=0CF8Q6AEwBQ#v=onepage&q=face%20mask%20football&f=false.
- McCarthy, John P.. Coaching Youth Football: The Guide for Coaches, Parents and Athletes. p. 20. http://books.google.com/books?id=iMI9j1sVHWEC&pg=PA20&dq=face+mask+football&hl=en&sa=X&ei=WU8MT9LHNIj40gGzv63OBQ&ved=0CFIQ6AEwAw#v=onepage&q=face%20mask%20football&f=false.