Helmet market, with deep Detroit ties, in arms race
NFL's Safest Helmets Absorb Impact With 3D Printing Instead Of Foam
NFL executive hints that Guardian Caps could eventually be worn in games, along with position-specific helmets
Future of NFL safety: Inside Vicis' high-tech football helmet production facility in Seattle – GeekWire
NFL to test new position-specific helmet designed for linemen
VICIS Zero1 top testing helmet NFL
Pat McAfee Reacts To NFL Approving New Position Specific Helmets
Chargers News: NFL, NFLPA approves first-ever position-specific helmets - Bolts From The Blue
What Pros Wear: Top 5 Helmets Rated by the NFL & NFLPA - What Pros Wear
VICIS ZERO1, Protect the athlete, elevate the game
NFL to prohibit use of certain helmets for 1st time – The Denver Post