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