Here's why some Patriots players are wearing caps over their helmets during training camp
NFL training camps: Guardian Cap players are wearing over helmets, why
The story behind those soft-shell puffy Guardian Caps players have been wearing
EXPLAINER: NFL using helmet caps for player safety, research
Eagles players on Guardian Caps: 'We look a little goofy,' but all for safety
What is the NFL Guardian Cap? Will it do anything to reduce concussion? — Dr. Mark Heisig
Guardian Caps debut at training camps throughout NFL
What is the NFL Guardian Cap? Will it do anything to reduce concussion? — Dr. Mark Heisig
LSU football reveals new air-conditioned helmets drawing rave reviews from players
High school football teams go soft in the fight against brain injuries
Raiders, other NFL teams wear Guardian Caps for head safety, Raiders News
NFL players wear Guardian Caps to reduce head trauma during training camp
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Unpopular guardian caps could provide false sense of security