For bootpacking and couloir crushing, these boots are trimmed of unnecessary weight. The QST line takes its fit cues from trail running shoes, and the Pro 100 TR combines cuff and shell material for flex and stiffness in the right spots, with an overlapping tongue to boost performance. The shell and liner are both heat mouldable so you can tweak the fit even further. Surelock technology keeps the boot securely in ski mode when it’s time to drop in.