San Francisco 49ers Full Size Authentic NFL Revolution Helmet by Riddell. This full size 49ers 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 San Francisco 49ers helmet is great for autographs and features 49ers team logo decals on both sides. The striking shape of the future. NFL 49ers Authentic helmet size is 13.5"(L) x 9.75"(W) x 10.25"(H). NFL San Francisco 49ers Full Size Revolution Helmet.