Florio PFT] The Guardian Cap apparently works. But if a player asks to wear it in a game, the league would say no. : r/nfl
As NFL mandates Guardian caps in practice, area high school football teams have been using them for years, Sports
Guardian Caps: NFL requires use of helmet cover at training camps to reduce head injuries : r/nfl
NFL's use of Guardian padded helmet caps in camp draws support and skepticism - The Athletic
NFL training camps: Guardian Cap players are wearing over helmets, why
From Purdy to Rodgers: the most important people in the new NFL season, NFL
Eagles' Britain Covey was turned away from player parking lot
Guardian cap' to prevent head injuries mandated for practices, CFL says
NFL hopes to reduce head injuries with helmet experiment
Guardian Caps - Are the soft-shelled football helmet covers effective at limiting head injuries? - ESPN