When the snow conditions are firm, nothing offers uphill security like ski crampons or, as they say in German, ”harscheisen”. Check out the video from the American Mountain Guide Association about when to use ski crampons.
Ski crampons attach to your bindings (or ski as in some aftermarket telemark solutions) and pivot under foot as you skin up the hill, so that they engage in the snow when you step down and pivot up as you lift and slide forward. They are not a replacement for skins. In fact, they must be used in tandem with skins. There is very little resistance or even change in the cadence of your stride when using ski crampons, but there is considerable benefit and grip as you step down and they engage.
If you know the feeling of “holding on” while skinning on firm snow or steep side-hills, imagine how much energy can be saved if each step is significantly more secure feeling. Well, that is what ski crampons do for you. They offer security and stability that is unmatched by skins. But, again, they are not a standalone climbing tool; they work in conjunction with your skins.
All of the alpine touring binding companies make crampons that fit their bindings: Dynafit crampons are compatible with all Dynafit binding models, G3 makes ‘em for the ION binding (read more about G3 ION ski crampons), Fritschi for the Vipec and Marker for the Kingpin. For telemark skiers, there are a couple of universal options available from Voile and B & D Ski Gear.
Ski Crampon ease of use varies, but for the most part they are designed to be installed on the fly and are easily removed when not needed. Obviously, you can live without ski crampons, but once you’ve experienced their added climbing security, you will be sold. There is very little weight or space penalty for carrying them, and the reward when the going gets firm is big.