NFL expands rule against misuse of helmet; Guardian Caps required in regular season, postseason
NFL fans react to new guardian cap rules
Guardian Cap Results: “Exceeded Our Expectations”
Large Bubble Helmets Are Guardian Caps, NFL's New Safety Measure
Steelers QB Kenny Pickett turning to new helmet technology to help avoid further concussions in 2023
Guardian Caps leave some NFL players and coaches with concerns: 'You feel like a bobblehead'
NFL mandates use of Guardian Caps for training camp in 2022 - Cincy Jungle
Funky-Looking Guardian Caps Rejected by NFL for Regulation Play, OK'd for Practice - Core77
Funky-Looking Guardian Caps Rejected By NFL For Regulation, 59% OFF
Guardian Cap Debuts at Training Camps League-wide