NFL training camps: Guardian Cap players are wearing over helmets, why
Guardian Caps - Are the soft-shelled football helmet covers effective at limiting head injuries? - ESPN
The story behind those soft-shell puffy Guardian Caps players have been wearing
The story behind those soft-shell puffy Guardian Caps players have been wearing
The story behind those soft-shell puffy Guardian Caps players have been wearing
NFL players experimenting with 'Guardian Caps' to prevent head injuries
High school football teams go soft in the fight against brain injuries
NFL says positions wearing Guardian Caps saw 52% decrease in concussions - NBC Sports
The story behind those soft-shell puffy Guardian Caps players have been wearing
Why Alabama football players are wearing padded helmets in practice
NFL players wear Guardian Caps to reduce head trauma during training camp
Coverage of the NFL in Guardian Caps
NFL could move to requiring Guardian Caps in games
Puffy, spongy Guardian Caps could help curb NFL head injuries - The Washington Post