What is a Guardian Cap? Meet the NFL's newest safety measure
Guardian Caps Exceed NFL's Expectations - Guardian Sports
CFL players adjust to protective helmet caps
Ravens Embrace the Funny-Looking Guardian Helmets - Sports
NFL training camps: Guardian Cap players are wearing over helmets, why
Guardian Caps: NFL requires use of helmet cover at training camps
What are Guardian Caps? NFL players sport specialty helmets for
Quotebook Notebook: Jason Kelce remains hungry in Year 12
What are Guardian Caps? Shadow Hills football using new device to
NFL executive: Guardian Caps could one day be used in games