This is Garmonts stiffest AT boot. They call it an AT flex rating of 130. This flex rating is only relative to other AT boots in Garmont's line-up and shouldn't be compared to other manufactures boots. In comparison the Radium is a AT 120. Changes from last year are: Main difference is the liner. The 2009-2010 version has Garmont's new Rapid liner. Denser, non thermoformable foam on the sole helps prevent pack out. Also, it has more toe room, due to thinner and elastic foam in the toes. Difference in the shell are new buckles and new colors.