Guardian Cap Use a Concern for Watt, Saleh Early in Training Camp - Sports Illustrated
NFL makes Guardian Caps mandatory for many positions through second preseason game - NBC Sports
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 exec suggests Guardian Caps worn to protect players during practices could one day debut in games
New NFL Helmets - NFL Testing Validates Benefit of Guardian Caps
NFL expands rule against misuse of helmet; Guardian Caps required in regular season, postseason
Guardian Caps: Why some NFL players are wearing them in training camps
It's time the NFL made Guardian Caps mandatory