What Pros Wear: Guardian Caps What are Those Helmet Covers Being Worn in Practice? - What Pros Wear
Padded helmet cover shows little protection for football players - Scope
CFL introduces mandatory extra helmet protection for multiple positions. As well as other new health & safety measures. : r/sports
NFL, NFLPA working hard to improve player safety
Could Guardian Caps be used during NFL games for player safety?, Pro Football Talk
Guardian Caps - Are the soft-shelled football helmet covers effective at limiting head injuries? - ESPN
Guardian Caps', NFL's Most Recent Attempt At Preventing Head Injuries
What are Guardian Caps? NFL players sport specialty helmets for 2022 minicamp
Concussions: Can cap keep football players' heads in game? – Orange County Register