Duke Blue Devils Full Size Speed Replica NCAA Helmet by Riddell. This full size Duke helmet is designed with a non-wear plate and molded foam jaw pads. a steel polyvinyl-coated face mask, 4-pt chin strap, and elliptical air vents. This officially licensed NCAA helmet is great for autographs and features Duke team logo decals on both sides. The striking shape of the future. NCAA Duke Replica Speed helmet size medium measures: 12.75"(L), 9.25"(W), 9.75"(H). NCAA Duke Blue Devils Full Size Speed Replica Helmet. (NOT FOR WEARING)