Guardian Caps: The new helmets worn by several NFL teams
EXPLAINER: NFL using helmet caps for player safety, research
Guardian Caps: What are they and why are NFL players wearing them? - Sactown Sports
Utah Utes football adds new concussion-reducing helmets for fall camp
Browns wearing Guardian Caps during training camp
Guardian Caps leave some NFL players and coaches with concerns: 'You feel like a bobblehead'
NFL training camps: Guardian Cap players are wearing over helmets, why
Wake Up Washington Commanders adjust to guardian caps at first practice of training camp
NFL players wear Guardian Caps to reduce head trauma during training camp