Wow. It's all I got for this amazing boot. The XT 100 has a 100 mm last, and a great 100 flex. This boot also has rubber soles which make it great for hiking. It also has a super easy to use ski/hike feature. This is Langes first hiking boot and they hit a home run. Ask Tyler, he is skiing this boot and loves it. So whether you are skiing on or off trail, this boot can do it all.