EXPLAINER: NFL using helmet caps for player safety, research
Guardian Cap - Soft-Shell Helmet Cover for Football and Lacrosse - Reduces Impact and Protects Helmets - One Size Fits All for Youth, High School and College Programs - Navy
Guardian Cap Debuts at NFL Training Camps League-wide
High schools try to cap concussions
Guardian Caps leave some NFL players and coaches with concerns: 'You feel like a bobblehead'
Eagles players on Guardian Caps: 'We look a little goofy,' but all for safety
NFL says positions wearing Guardian Caps saw 52% decrease in concussions - NBC Sports
Eagles players on Guardian Caps: 'We look a little goofy,' but all for safety
Guardian Caps Guardian Sports
Guardian Caps debut at NFL training camps around the league
Guardian cap' to prevent head injuries mandated for practices, CFL says
Puffy Guardian Caps Could Reduce NFL Player Concussions
Guardian Cap: What are and why the NFL asks this safety measure in helmets