If you are unfamiliar with climbing skins, they are strips of material attached under skis to aid with climbing. They have an elasticised hoop at the top that hooks over the spatula of the ski. On one side they are covered with short-hairs, rather like a No. 2 cut from the local barber shop, the other has sticky glue. which adheres to the base of the ski. The hairs are either nylon or mohair or a mix of the two. Mohair mixes offer a good compromise between cost/durability and performance. The end of the climbing skin might have a hook to clip over the back of the ski, a point where the skis often come unglued during a long tour. The hairy side lets the ski glide forward but grips fast to the snow, even on quite acute angles. A skier can ascend a black piste with ease and steeper slopes can be climbed in a series of linked kick turns called conversions in French.
With the adoption of shaped skis for touring there is debate as to whether skins should cover the entire base of the ski leaving just the edges free to assist grip when traversing slopes or whether straight skins should be used. When skis were pretty much straight this was easy, you simply bought a skin that was as wide as the narrowest point of your ski. We recommend that you buy a ski that has a corresponding skin available or that you can buy a skin as wide as the spatula of your ski. This is cut to shape by trimming with a very sharp knife around the edge of the ski. For the second cut the skin should be moved a millimetre or two to ensure that both edges are visible when the skin is used. It has also been suggested using their old skins but cutting them down the middle so sticking the two parts on the edge but leaving a section in the middle uncovered. Whatever method you choose it is much easier to climb where the outer surfaces of the base are covered.