Michigan Wolverines Riddell SpeedFlex Authentic Football Helmet. The SpeedFlex helmet has quickly become the most popular helmet of choice by top NCAA & NFL players. The officially licensed Michigan Wolverines Riddell SpeedFlex helmet is the most authentically-inspired collectible in our line and is the perfect item for autographs and collectors. Complete with comfort overliner and SF-2B-SW facemask with quick release facemask attachments the helmet also features Wolverines team logo decals on both sides. The unmistakable look of the Riddell SpeedFlex has become the new icon of the game. NCAA Michigan Wolverines Riddell SpeedFlex Authentic Football helmet size is 13.5"(L) x 9.75"(W) x 10.25"(H)