Seattle Seahawks Full Size Authentic Revolution Speed NFL Helmet by Riddell. This full size helmet is designed with extended mandible (jaw area) protection, a steel polyvinyl-coated face mask, chin strap, increased padding, an integrated facemask attachment system and elliptical air vents. The officially licensed helmet is great for autographs and features team logo decals on both sides NFL Authentic Revolution Speed helmet size is 13.5"(L) x 9.75"(W) x 10.25"(H). NFL Full Size Helmet.