What are Guardian Caps and how are they helping football teams?
NFL Mandates Guardian Caps During Training Camp - Team Insight
Chicago Bears: Why players are wearing padded helmets
What's with padded helmet caps teams are wearing
NFL's use of Guardian padded helmet caps in camp draws support and
Guardian Caps: NFL requires use of helmet cover at training camps
NFL players wear Guardian Caps to reduce head trauma during
Carolina Panthers NFL helmets training camp
Steelers debut new, safer helmets for off-season training
Large Bubble Helmets Are Guardian Caps, NFL's New Safety Measure