Kansas City Chiefs Full Size Authentic Revolution Speed NFL Helmet by Riddell. This full size Chiefs 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. NFL Team name on back bumper (except Chiefs, Steelers and Giants). The officially licensed Kansas City Chiefs helmet is great for autographs and features Chiefs team logo decals on both sides. The striking shape of the future. NFL Chiefs Authentic Revolution Speed helmet size is 13.5"(L) x 9.75"(W) x 10.25"(H). NFL Kansas City Chiefs Full Size Helmet.