NFL hopes to reduce head injuries with helmet experiment
NFL mandates extra head protection for training camp
What is a Guardian Cap? Meet the NFL's newest safety measure
Concussions Dropped More Than 50 Percent for Players Who Wore
Football Guardian Cap draws mixed reviews from players, experts
EXPLAINER: NFL using helmet caps for player safety, research
Guardian cap' to prevent head injuries mandated for practices, CFL
Eagles players on Guardian Caps: 'We look a little goofy,' but all
Carolina Panthers NFL helmets training camp
Guardian Cap used by football teams to protect against head injury