Guardian Caps: The new helmets worn by several NFL teams
Playing with a pillow on your head': Buffalo Bills embrace new helmet covers
NFL CMO Dr. Allen Sills explains importance of mandated guardian caps during training camp
NFL executive hints that Guardian Caps could eventually be worn in games, along with position-specific helmets
Guardian Caps The Rundown
Why the Ticats are wearing those giant helmets at practice
EXPLAINER: NFL using helmet caps for player safety, research
Puffy, spongy Guardian Caps could help curb NFL head injuries - The Washington Post
What are Guardian Caps? NFL's latest padded helmets for added safety
Guardian Caps leave some NFL players and coaches with concerns: 'You feel like a bobblehead'
Guardian Caps: NFL requires use of helmet cover at training camps to reduce head injuries : r/nfl