NFL players experimenting with 'Guardian Caps' to prevent head injuries
NFL executive hints that Guardian Caps could eventually be worn in games, along with position-specific helmets
NFL players beginning to adopt protective Guardian Caps over helmets at practice - NBC Sports
What are those funny-looking soft caps on NFL helmets during camp?, Sports
Guardian Caps leave some NFL players and coaches with concerns: 'You feel like a bobblehead'
Padded helmet cover shows little protection for football players - Scope
Morse says 'Halo' helmets making a difference
NFL CMO Dr. Allen Sills explains importance of mandated guardian caps during training camp
Guardian Caps: NFL requires use of helmet cover at training camps to reduce head injuries
What's With Those Padded Caps NFL Players Are Wearing In Training Camp?
Badgers wearing Guardian Caps to limit concussions during practice
NFL Mandated Guardian Caps: Controversial Change - Sports Illustrated Seattle Seahawks News, Analysis and More