The King of the Hammers (KOH) is known as the toughest off-road race in the world but Polaris Factory Racer Mitch Guthrie and his co-driver Mitch Guthrie Jr. are tougher winning their sixth Hammer in seven years, all in Polaris RZRs.Thirty-four Pro Class side-by-sides, predominately RZRs, would line up to try to take the Hammer and a brand-new 2015 RZR XP 1000 EPS, which was offered to the Pro Class winner as part of Polaris RZR being the official side-by-side of the race.