Guardian Caps: Why some NFL players are wearing them in training camps
Puffy, spongy Guardian Caps could help curb NFL head injuries
NFL executive hints that Guardian Caps could eventually be worn in
Guardian Caps: Why some NFL players are wearing them in training camps
More Guardian Caps, And '0' On The Field
Bombers welcome introduction of new safety gear – Winnipeg Free Press
What Pros Wear: Guardian Caps What are Those Helmet Covers Being
Arizona Cardinals defensive end J.J. Watt not fan of the new
NFL players wear Guardian Caps to reduce head trauma during
PLA donates guardian helmet caps to Onekama football program
Padded helmet cover shows little protection for football players
Experts: Helmet improvement not perfect solution to concussions