What are those funny-looking soft caps on NFL helmets during camp?, Sports
NFL players don Guardian Caps, designed to protect from concussion
Get A Load Of These Big Dumb Helmet Helmets
For Giants and the NFL, it's the Summer of Guardian Caps - Newsday
What are Guardian Caps and how are they helping football teams?
Chicago Bears: Why players are wearing padded helmets
Here's why some Patriots players are wearing caps over their helmets during training camp
Eagles Notes: New Guardian Caps get mixed reviews – Delco Times
Padded helmet cover shows little protection for football players - Scope
Steelers debut new, safer helmets for off-season training
NFL training camps: Guardian Cap players are wearing over helmets, why
Why are some Titans players wearing Guardian Caps during training camp?, Titans
NFL Guardian Caps: How Do They Work? – NBC 5 Dallas-Fort Worth