The two networks who broadcast NFL games on Sunday afternoons — Fox and CBS — both typically air doubleheaders during the regular season (with the other network only being permitted to broadcast one game in a specific market), with restrictions applying to some markets in which the local team is playing at home that week. When combined with the Sunday night game on NBC, this creates a tripleheader (as was sometimes advertised by the league's radio partner, Westwood One, which carried three games in a tripleheader).