In the United States and Canada, the term football usually refers to a ball made of cow hide leather, which is required in professional and collegiate football. Footballs used in recreation and in organized youth leagues may be made of rubber or plastic materials (the high school football rulebooks still allow the inexpensive all-rubber footballs, though they are less common than leather). Since 1941, Horween Leather Company has been the exclusive supplier of leather for National Football League footballs. The arrangement was established by Arnold Horween, who had played and coached in the NFL. Horween Leather Company also supplies leather to Spalding, supplier of balls to the Arena Football League.