Guardian Caps: Why some NFL players are wearing them in training camps
NFL CMO Dr. Allen Sills explains importance of mandated guardian caps during training camp
Guardian Caps - Are the soft-shelled football helmet covers effective at limiting head injuries? - ESPN
What are those funny-looking soft caps on NFL helmets during camp?, Sports
NFL Expands Use Of Guardian Caps In 2023 - Steelers Depot
Eagles players on Guardian Caps: 'We look a little goofy,' but all for safety
NFL players beginning to adopt protective Guardian Caps over helmets at practice - NBC Sports
NFL players experiment with Guardian Caps // Guardian Sports
Steelers debut new, safer helmets for off-season training