Guardian Caps Guardian Sports
Concussions among players who wore Guardian Caps over summer dropped more than 50%, NFL says - ESPN
Guardian Caps: Why some NFL players are wearing them in training camps
NFL hopes to reduce head injuries with helmet experiment
Playing with a pillow on your head': Buffalo Bills embrace new helmet covers
NFL players wear Guardian Caps to reduce head trauma during training camp
NFL: Concussions dropped by more than 50% among players who wore Guardian Caps during summer
Coverage of the NFL in Guardian Caps
NFL Executive VP: League Saw 52 Percent Decrease In Concussions At Positions Wearing Guardian Caps - Steelers Depot