MTSU reduces concussion risk with padded helmet covers
Guardian Caps: What Are They & How Do They Work?
Guardian Caps: Why some NFL players are wearing them in training camps
Guardian Caps: Why some NFL players are wearing them in training camps
Puffy, spongy Guardian Caps could help curb NFL head injuries - The Washington Post
Here's why some Patriots players are wearing caps over their helmets during training camp
Puffy, spongy Guardian Caps could help curb NFL head injuries - The Washington Post
NFL executive hints that Guardian Caps could eventually be worn in games, along with position-specific helmets
Guardian Caps added to help reduce football concussions - The Witmarsum
Safety first: Lopers to wear padded caps in practice to prevent concussions
Why Alabama football players are wearing padded helmets in practice
Guardian Caps, a soft-shell helmet cover, among CFL's new player-safety initiatives