NFL players beginning to adopt protective Guardian Caps over helmets at practice - NBC Sports
Why are NFL players wearing padding on helmets at training camp?
Guardian Caps, a soft-shell helmet cover, among CFL's new player-safety initiatives
NFL mandates guardian caps Archives - Guardian Sports
Guardian Cap debuts during minicamps in effort to reduce avoidable head contact
Guardian Caps: NFL requires use of helmet cover at training camps to reduce head injuries
Guardian Caps: Why some NFL players are wearing them in training camps
NFL CMO Dr. Sills on Guardian Caps Mandate >> Guardian Sports
More padding the issue of concussions and better helmets
Guardian Caps are the latest effort to address CTE, football concussion concerns
NFL hopes to reduce head injuries with helmet experiment
Ravens Embrace the Funny-Looking Guardian Helmets - Sports Illustrated Baltimore Ravens News, Analysis and More
NFL report: concussions dropped 50 PERCENT when players wore new 'Guardian Caps' over the summer
NFL says positions wearing Guardian Caps saw 52% decrease in concussions - NBC Sports
Guardian cap' to prevent head injuries mandated for practices, CFL says