Puffy, spongy Guardian Caps could help curb NFL head injuries - The Washington Post
Guardian Cap debuts during minicamps in effort to reduce avoidable head contact
NFL hopes to reduce head injuries with helmet experiment, Taiwan News
Bombers set to don Guardian Caps” on helmets at training camp
Guardian Cap Debuts at Training Camps League-wide
NFL Testing Safer Helmets
NFL's use of Guardian padded helmet caps in camp draws support and skepticism - The Athletic
Guardian Cap Debuts at Training Camps League-wide
Why are NFL players wearing padding on helmets at training camp?
Guardian Caps leave some NFL players and coaches with concerns: 'You feel like a bobblehead'
NFL executive hints that Guardian Caps could eventually be worn in games, along with position-specific helmets
NFL players will honor racism victims with names on helmet decals