Puffy, spongy Guardian Caps could help curb NFL head injuries
What are Guardian Caps and how are they helping football teams?
EXPLAINER: NFL using helmet caps for player safety, research
Ban on helmet covers sparks controversy
Guardian cap' to prevent head injuries mandated for practices, CFL
Why are some Titans players wearing Guardian Caps during
NFL CMO Dr. Allen Sills explains importance of mandated guardian
Guardian Caps leave some NFL players and coaches with concerns