Puffy, spongy Guardian Caps could help curb NFL head injuries - The Washington Post
What are Guardian Caps? NFL's latest padded helmets for added safety
Shell game: Player safety looming concern as new season approaches, Local Sports
What Are the Experts Saying About Guardian Caps – The Concussion Blog
Guardian Cap Use a Concern for Watt, Saleh Early in Training Camp - Sports Illustrated
Alex Rodriguez: cheat, liar, egomaniac and baseball's savior, MLB
Smith] NFL says positions wearing Guardian Caps saw 52% decrease in concussions : r/nfl
NFL hopes to reduce head injuries with helmet experiment
So what exactly is that black padding on the Syracuse football helmets seen during practice?
Football helmet - Wikipedia
Football helmet - Wikipedia