Guardian Caps: NFL requires use of helmet cover at training camps
2012 Army Football Media Guide by Army West Point Athletics - Issuu
NFL expands rule against misuse of helmet; Guardian Caps required
Funky-Looking Guardian Caps Rejected by NFL for Regulation Play
NFL CMO Dr. Sills on Guardian Caps Mandate >> Guardian Sports
EXPLAINER: NFL using helmet caps for player safety, research
NFL executive hints that Guardian Caps could eventually be worn in
What are Guardian Caps? NFL's latest padded helmets for added safety
Guardian Cap Debuts at Training Camps League-wide
Why are NFL players wearing padding on helmets at training camp?
What Pros Wear: Guardian Caps What are Those Helmet Covers Being
What Pros Wear: Guardian Caps What are Those Helmet Covers Being