Guardian Caps - Are the soft-shelled football helmet covers effective at limiting head injuries? - ESPN
NFL Presents: League-wide Guardian Cap Use to Reduce Head Impacts
Puffy, spongy Guardian Caps could help curb NFL head injuries - The Washington Post
NFL training camps: Guardian Cap players are wearing over helmets, why
Patriots Camp Notes and Morse's Morsels
What Pros Wear: Guardian Caps What are Those Helmet Covers Being Worn in Practice? - What Pros Wear
NFL Guardian Caps: How Do They Work? – NBC 5 Dallas-Fort Worth
CFL players adjust to their bigger heads, helmet covers worn in practice
Guardian Cap Debuts at Training Camps League-wide
The story behind those soft-shell puffy Guardian Caps players have been wearing
Coverage of the NFL in Guardian Caps
Guardian Caps Debut at Training Camps Across the NFL
NFL Notes: Chargers-Saints Takeaways, New MNF Crew Debuts Tonight, More
First Call: Chase Claypool, Damar Hamlin starting to pop in camps; replay rule change; Guardian Caps in games?
NFL Introduces Guardian Caps At First Week Of Training Camp - The Sports Credential