What Pros Wear: Guardian Caps What are Those Helmet Covers Being Worn in Practice? - What Pros Wear
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What's with padded helmet caps teams are wearing
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NFL hopes to reduce head injuries with helmet experiment
Guardian Cap Use a Concern for Watt, Saleh Early in Training Camp - Sports Illustrated
First QB helmet designed to help reduce concussions approved by NFL, NFLPA
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Guardian cap' to prevent head injuries mandated for practices, CFL says