Puffy, spongy Guardian Caps could help curb NFL head injuries - The Washington Post
Patriots training camp Day 1: Mac Jones sizzles, Matt Patricia calls plays and a new receiver shines – Boston Herald
NFL mandates use of Guardian Caps for training camp in 2022 - Cincy Jungle
Guardian Caps Debut at Training Camps Across the NFL
Football helmet - Wikipedia
Steelers debut new, safer helmets for off-season training
NFL exec suggests Guardian Caps worn to protect players during practices could one day debut in games
Guardian Cap Debuts at Training Camps League-wide
Guardian Cap Debuts at NFL Training Camps League-wide
NFL report: concussions dropped 50 PERCENT when players wore new 'Guardian Caps' over the summer
EXPLAINER: NFL using helmet caps for player safety, research
Coverage of the NFL in Guardian Caps
Guardian Caps debut at training camps throughout NFL
NFL's use of Guardian padded helmet caps in camp draws support and skepticism - The Athletic
Guardian Caps debut at NFL training camps around the league