The Superior is Altra's ultralight trail running shoe, designed with just the essentials in mind and pushing aside all the extras. The Quantic foam mid sole is trimmed down to the minimum and is fairly flexible, resulting in a very responsive shoe that feel feather light on your feet. The upper is constructed with a wrap-around tongue that has a sock-like fit on the mid-foot and is one of our favorite features of the shoe. The revised version 4.5 is slightly wider that the previous model, but with minor tweaks to the upper to snug the fit up a bit as well. If you're pushing your limits on Eastside side and want the lightest possible shoe, come try these on.