Arizona Cardinals defensive end J.J. Watt not fan of the new league-mandated Guardian Caps on helmets
Guardian Caps: NFL requires use of helmet cover at training camps to reduce head injuries : r/nfl
No cap: Guardian covers are out, but one Steelers lineman plans to keep wearing it
Guardian Caps: The new helmets worn by several NFL teams
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
Large Bubble Helmets Are Guardian Caps, NFL's New Safety Measure
Guardian Caps - Are the soft-shelled football helmet covers effective at limiting head injuries? - ESPN
Do Padded Helmet Covers Actually Protect Football Players? - The Good Men Project
Why are NFL players wearing padding on helmets at training camp?
Guardian Caps: NFL requires use of helmet cover at training camps to reduce head injuries
Guardian Caps, a soft-shell helmet cover, among CFL's new player-safety initiatives