NFL: Concussions dropped by more than 50% among players who wore Guardian Caps during summer
NFL hopes to reduce head injuries with 'goofy' helmet experiment
NFL exec suggests Guardian Caps worn to protect players during practices could one day debut in games
Guardian Caps Guardian Sports
Puffy, spongy Guardian Caps could help curb NFL head injuries - The Washington Post
The story behind those soft-shell puffy Guardian Caps players have been wearing
Guardian Cap Use a Concern for Watt, Saleh Early in Training Camp - Sports Illustrated
NFL's use of Guardian padded helmet caps in camp draws support and skepticism - The Athletic
Cowboys seen wearing protective, NFL mandated Guardian Caps at OTAs
Guardian Caps: Why some NFL players are wearing them in training camps
Guardian cap' to prevent head injuries mandated for practices, CFL says
NFL training camp 2022: Why are players wearing Guardian Caps?
EXPLAINER: NFL using helmet caps for player safety, research
Steelers players wearing caps at training camp