same basic design as the ace of spades (modified cabrio). Mabye some people who have extensive knowledge of that boot can give you some info especially about their "progressive flex". But i'm contractually obligated to say see a bootfitter, if they fit ur foot well, and fall within the flex boundaries of what ur looking for buy them. The design really isn't that different from alot of boots on the market right now (dalbello Axion, blender, boss; fulltilt booter, high five; and the nordica boots themselves Ace of Spades, double six, and dead money). IMO the new "flex rating" is more of a sales gimmick to set the brand apart from all of the others, not to say that they aren't good boots though.