Adrian Peterson Signed Oklahoma Sooners Speed Mini Helmet (Beckett) Vikings R.B.Riddell Oklahoma Sooners speed mini helmet. Hand signed and inscribed by Adrian Peterson. Please note, it has the classic upside down Longhorns Decal, which is one of the most recognized hand signals of all American universities. A variant of the Horns, formed upside down with the thumb pointed outward, is often used by rivals of the Longhorns and is considered insulting, especially when performed by a player or coach of the team in question. The