NFL CMO Dr. Sills on Guardian Caps Mandate >> Guardian Sports
What are Guardian Caps and how are they helping football teams?
Guardian Caps Exceed NFL's Expectations - Guardian Sports
NFL mandates guardian caps Archives - Guardian Sports
Carolina Panthers NFL helmets training camp
NFL executive hints that Guardian Caps could eventually be worn in games, along with position-specific helmets
Guardian Caps: Why some NFL players are wearing them in training camps
Chiefs TE Travis Kelce thinks NFL's mandated 'Guardian Caps' are silly
Complaints begin regarding Guardian Caps, despite one important hidden benefit - NBC Sports
EXPLAINER: NFL using helmet caps for player safety, research