Guardian Caps: Why some NFL players are wearing them in training camps
What Pros Wear: Guardian Caps What are Those Helmet Covers Being Worn in Practice? - What Pros Wear
NFL Releases Concussion Data After Use of 'Guardian Caps' During Offseason - Sports Illustrated
NFL players wear Guardian Caps to reduce head trauma during training camp
Concussions among players who wore Guardian Caps over summer dropped more than 50%, NFL says - ESPN
Puffy, spongy Guardian Caps could help curb NFL head injuries - The Washington Post
What Pros Wear: Guardian Caps What are Those Helmet Covers Being Worn in Practice? - What Pros Wear
NFL Mandate of Guardian Caps - 2023 Season >> Guardian Sports
Funky-Looking Guardian Caps Rejected by NFL for Regulation Play, OK'd for Practice - Core77