The binding is the defining feature of an AT setup. It holds your boot much like an Alpine binding does, but it's lighter and less cumbersome. A simple adjustment frees the heel while keeping the toe hinged, allowing you to hike uphill on your skis with a natural stride. All bindings incorporate several climbing modes, which lets you raise the height of the platform your boot heel rests on-a lower-leg lifesaver on steeper ascents.
At first, it may feel weird-and a little unstable-to be able to move your heel up and down, but it's a heck of a lot better than trying to herringbone or sidestep up the hill. Just don't forget to lock down your heels before the descent, or you'll end up kissing your ski tips.
The most Alpinelike AT binding is the step-in Fritschi Diamir 2 ($339). It has four heel levels for touring and is easy to change from climbing to skiing mode with the flick of a ski pole. Silvretta, a classic name in AT bindings, recently introduced the step-in Easy Go ($375), made of lightweight but strong carbon fiber. This binding, like other Silvrettas, uses a bail to hold the boot toe in place, which means it can be used with plastic mountaineering boots as well as randonnée-specific gear. The lightest binding available is the Dynafit TourLite Tech ($320), which holds one of four companion Dynafit boot models in place with a system of pins in the heel and toepiece. Because this binding is so minimalist (and relatively difficult to step into), it may take hardcore Alpine skiers a bit longer to get used to, but its light weight is a worthy payoff.