Chiefs TE Travis Kelce thinks NFL's mandated 'Guardian Caps' are silly
Guardian cap' to prevent head injuries mandated for practices, CFL says
The story behind those soft-shell puffy Guardian Caps players have been wearing
What in the world are those weird-looking helmets the Saints are wearing in camp?, Rod Walker
Mac Jones 'works his butt off' says fellow Patriots QB Brian Hoyer - Pats Pulpit
Guardian Caps - Are the soft-shelled football helmet covers effective at limiting head injuries? - ESPN
Guardian Caps: Why some NFL players are wearing them in training camps
NFL permitting players to display social justice messages on helmets this season - The Boston Globe
Puffy, spongy Guardian Caps could help curb NFL head injuries - The Washington Post
NFL CMO Dr. Allen Sills explains importance of mandated guardian caps during training camp
Guardian Cap Debuts at Training Camps League-wide
Guardian Caps debut at training camps throughout NFL
Cowboys wearing soft-shell helmets in practice as part of NFL mandate