St. Louis Rams Full Size Authentic NFL Revolution Helmet by Riddell. This full size Rams 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 St. Louis Rams helmet is great for autographs and features Rams team logo decals on both sides. The striking shape of the future. NFL Rams Authentic helmet size is 13.5"(L) x 9.75"(W) x 10.25"(H). NFL St. Louis Rams Full Size Revolution Helmet.