K2 radical 100 has been a top pick for the performance minded skater over the past four years since its 2005 debut and has a cool new look for the 2012 season. Radical 100's are designed for long training skates and marathon skating. They are equipped to thrill! The radical cuff is a contoured, low cut cuff that equally fits women and men due to the scalloped rear. The maximum forward flex positions skaters in a low and powerful skating position while perfectly supporting the ankles. "Passing on the left!" Compared to the discontinued Rad 90, the Radical 100's main advantage is that it has 10mm larger wheels. Since the only real difference between the Rad 90 and Rad 100 is the wheel size and frame length, K2 discontinued the Rad 90. Thus, if you want a feather light skate, huge 100mm wheels, and a low ankle cuff, go for the Radical 100! If you want the extra speed the Radical Pro offers, and you are willing to take on a little extra weight and length in the frame and wheels, the Radical Pro is the skate for you. On the positive side, the 100mm Star Grip poured wheels and Longmount Frame, does offer unbelievable forward stability. Something everybody needs at the end of a long exhaustive training run, or marathon. So, whether you are out for your daily training run or competing, the K2 radical 100 is a great choice.