Guardian Cap: What are and why the NFL asks this safety measure in helmets
The story behind those soft-shell puffy Guardian Caps players have been wearing
NFL players don Guardian Caps, designed to protect from concussion
Coverage of the NFL in Guardian Caps
NFL players wear Guardian Caps to reduce head trauma during training camp
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What are those funny-looking soft caps on NFL helmets during camp?, Sports
NFL mandates use of Guardian Caps for training camp in 2022 - Cincy Jungle
Guardian Cap Use a Concern for Watt, Saleh Early in Training Camp - Sports Illustrated
Puffy, spongy Guardian Caps could help curb NFL head injuries - The Washington Post
Why are NFL players wearing padding on helmets at training camp?
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