As I found during six weeks of training for the Power of Four race in Aspen, Colorado, ski-mountaineering is one of the most physically demanding and fun sports you can do. For first-timers, the difference between liking it and loving it often comes down to gear. A less-than-totally windproof pair of gloves, skins that won’t effortlessly glide, or base layers that trap sweat will derail workouts, leaving you cold and frustrated. During training, my ski-mo racing partner Eric Henderson and I tested a warehouse worth of gear. Here, we boiled down the best of the essentials, and everything you need to get started.