104mm last: Comfort is key for skiers matching up to this last width. It is roomy and comfortable, making it the preferred choice for recreational skiers that demand comfort above all else. This is the boot type that most recreational skiers prefer.
70 Flex Index: This boot has a flex rating of 70, which is best suited for beginner and intermediate skiers. Softer boots will be more comfortable, but won't offer enough stability at higher speeds. Stiffer than 70 will give that stability, but start to get a little less comfortable.
Ski-Walk Flip Lever: The back of the boot sports a lever to be pushed up or down to transfer from walk and ski modes, respectively. The walk mode allows the cuff to slide forward and back, where the ski mode locks the boot in a forward, skiing stance.
30mm Power Strap: A velcro strap, 30mm in height, acts as an extra buckle to keep the top of the boot together. The 30mm straps are good for recreational skiers or junior racers.
Macro adjust ladder (SuperMacro): The tooth plate opposite the top buckles can be moved in or out for a huge range of adjustment, and to fit narrow to wide lower legs.
Full Thermo Fit Liner: Body heat activates the material in this liner to shape to the skier's foot faster than a standard liner. The insulation also has heat reflective properties to keep the warm in, and the cold out.
Micro-adjustable aluminum buckles: These aluminum buckles can be moved to adjust for size, so if the default position of the buckle and the teeth is too wide or too narrow, you can move it until it fits.
The Big Fella Corollary: We list flex indexes and generally that will be how you determine the level of a ski boot. For ski boots that are very large, you can also take into account the size of the skier using the boots. A 6'5 260lb guy is going to flex his boots more easily than a more averaged sized man, and hence need to ski less aggressively than the flex might indicate. So maybe the boot says it's an upper-intermediate boot, but if he is a Big Fella that is only a lower-intermediate, he still will be able flex the boot comfortably. (The same is true of ladies, but 'Big Bertha' Corollary seemed sort of offensive).