Jason Kelce puts bubblewrap on his helmet, mocking the NFL's dumb new Guardian Cap rules in training camp
Puffy, spongy Guardian Caps could help curb NFL head injuries - The Washington Post
Football helmet - Wikipedia
Football helmet - Wikipedia
NFL: Concussions dropped by more than 50% among players who wore Guardian Caps during summer
Australian Philadelphia Eagles NFL star Jordan Mailata calls bizarre-looking safety gear 'fake news'
NFL hopes to reduce head injuries with helmet experiment
So what exactly is that black padding on the Syracuse football helmets seen during practice?
Guardian Caps - Are the soft-shelled football helmet covers effective at limiting head injuries? - ESPN