Seattle Seahawks players talk about their experience wearing new high-tech Vicis helmet – GeekWire
Guardian Caps', NFL's Most Recent Attempt At Preventing Head Injuries
The Football Player's Brain That Sparked the NFL's Concussion Crisis - The Atlantic
Almost all players in NFL now using top-performing helmets
Why Cowboys' Ezekiel Elliott is wearing a futuristic helmet for 2022 NFL season
Funky-Looking Guardian Caps Rejected by NFL for Regulation Play, OK'd for Practice - Core77
NFL hopes to reduce head injuries with helmet experiment
What was the deal with OBJ's visor? - Dawgs By Nature
49ers C Alex Mack Has Two Noteworthy Features: Weird Helmet, Sweating - Sports Illustrated Cal Bears News, Analysis and More
What Pros Wear: Top 5 Helmets Rated by the NFL & NFLPA - What Pros Wear
NFL training camps: Guardian Cap players are wearing over helmets, why
Do NFL players get new helmets for each game? - Quora
Wild facemasks of the NFL
What's up with the weird helmets? - OUInsider