Large Bubble Helmets Are Guardian Caps, NFL's New Safety Measure
The story behind those soft-shell puffy Guardian Caps players have been wearing
Guardian Caps', NFL's Most Recent Attempt At Preventing Head Injuries
NFL's use of Guardian padded helmet caps in camp draws support and skepticism - The Athletic
NFL players wear Guardian Caps to reduce head trauma during training camp
NFL hopes to reduce head injuries with helmet experiment
Reports of Montecito Being Exclusive to the Newly Wed and Nearly Dead Turn Out to Have Been Greatly by Montecito Journal - Issuu
Concussions among players who wore Guardian Caps over summer dropped more than 50%, NFL says - ESPN