Puffy, spongy Guardian Caps could help curb NFL head injuries - The Washington Post
NFL hopes to reduce head injuries with helmet experiment - Wilmington News Journal
Jonathan Allen clearly isn't a fan of NFL's mandated safety helmets
NFL players don Guardian Caps, designed to protect from concussion
What is a Guardian Cap? Meet the NFL's newest safety measure
EXPLAINER: NFL using helmet caps for player safety, research
Patriots players don Guardian Caps in an effort to curb concussions - Boston News, Weather, Sports
Giants react to NFL's new 'Guardian Caps' at training camps - Big Blue View
Puffy Guardian Caps Could Reduce NFL Player Concussions
The 2023 Uni Watch NFL Season Preview - by Paul Lukas