MLB pitcher head protection coming in spring
Guardian Cap - Soft-Shell Protective Helmet Cover : Football Helmets : Sports & Outdoors
What are those funny-looking soft caps on NFL helmets during camp?, Sports
Morse says 'Halo' helmets making a difference
Ravens Embrace the Funny-Looking Guardian Helmets - Sports Illustrated Baltimore Ravens News, Analysis and More
NFL hopes to reduce head injuries with helmet experiment
NFL training camps: Guardian Cap players are wearing over helmets, why
Leatherhead to Radio-head: The Evolution of the Football Helmet, Arts & Culture
Guardian Caps, a soft-shell helmet cover, among CFL's new player-safety initiatives
What are Guardian Caps? Shadow Hills football using new device to reduce head injuries