The first hybrid boot of its kind, the Arc'teryx Procline is either the most agile ski boot we’ve ever tried or the only alpine climbing boot that we’ve ever skied in. The special sauce is a two-piece carbon fiber cuff system that can rotate both forward and back (a whopping 75 degrees) and laterally (35 degrees) in walkmode. Unsurprisingly, it tours great (your ankle typically flexes between 55 and 75 degrees when walking), but we really appreciated the lateral movement when sidehilling and scrambling through mixed terrain with our skis on our backs. When the two buckles and power strap were locked down, we didn’t have any trouble slaying a 40-degree chute on the Spearhead Traverse. (But don’t expect resort-boot prowess when straightlining or plowing through heavy snow.) Credit the carbon rear plate and cuff for the rigidity. The Procline comes with one of two liners: The skiing-specific one—which we tested—is a touch thicker with a reinforced tongue, while the mountaineering-specific one is lighter. There’s no price difference. Comes in sizes 23-30.5.