Great for extreme endurance racing and trail running The North Face Ultra 103 XCR offers the same sort of waterproof and breathable GORE-TEX® XCR® found in other running shoes but this shoe has a little more open-cell sandwich mesh material along the upper for potentially better vapor transfer on long runs. For years running shoe manufacturers have mastered the art of waterproofing their trail running shoes but the real trick is finding a way to keep vapor transfer going as a runner's foot heats up. Even with a waterproof membrane trail running shoes that offer wide mesh panels often sacrifice essential support for navigating challenging trail terrain. The North Face Ultra 103 XCR features an extensive pattern of side and top open-cell sandwich mesh reinforced with synthetic leather and a special molded TPU lateral medial support system so you experience an effective balance between essential support and better breathable vapor transfer. Other support refinements include X-2™ air cushioning in the heel and fore foot and a Extended Roll Control™ medial heel wedge. The North Face Ultra 103 XCR is a great shoe for training on trails and it's still light enough for ultra-distance endurance racing in almost any weather.