NFL CMO Dr. Allen Sills explains importance of mandated guardian caps during training camp
NFL Training Camp: 12 photos of players wearing the new Guardian Caps
Guardian Caps debut at training camps throughout NFL
NFL hopes to reduce head injuries with helmet experiment
Helmets don't eliminate concussions. It's time for the NFL to ditch them, NFL
Guardian Cap Debuts at Training Camps League-wide
NFL hopes to reduce head injuries with helmet experiment
NFL's use of Guardian padded helmet caps in camp draws support and skepticism - The Athletic
NFL report: concussions dropped 50 PERCENT when players wore new 'Guardian Caps' over the summer
NFL training camps: Guardian Cap players are wearing over helmets, why
NFL exec suggests Guardian Caps worn to protect players during practices could one day debut in games