Guardian Caps - Are the soft-shelled football helmet covers effective at limiting head injuries? - ESPN

Wearing protective shells over helmets are becoming more popular as a means of possibly limiting head injuries in football -- but are they actually effective?

Football Guardian Cap XT – Red – Guardian Sports

Guardian Caps - Are the soft-shelled football helmet covers

Browns' Ryan Miller out of hospital after concussion

Puffy, spongy Guardian Caps could help curb NFL head injuries - The Washington Post

Guardian Caps Guardian Sports

Puffy Guardian Caps Could Reduce NFL Player Concussions

ONE SIZE FITS ALL | These padded covers will fit all youth & adult football and lacrosse helmets. Guardian Caps Helmet Covers are used by youth, high

Guardian Cap - Soft-Shell Helmet Cover for Football and Lacrosse - Reduces Impact and Protects Helmets - One Size Fits All for Youth, High School, and

Oklahoma Sooners Continue to be Proactive in Player Safety With Guardian Caps - Sports Illustrated Oklahoma Sooners News, Analysis and More

Can new technology help cut down on concussions? (video)