Mammut Aconcagua Light ML Jacket Color: Graphite Melange The light version of our classic performance fleece, this technical midlayer is all bang and no bulk. Designed to solve for a whole range of outdoor activities, its Polartec Power Grid fleece fabric offers high breathability and efficient moisture management at an incredible warmth-to-weight ratio. With a lightweight construction, soft hand-feel, and close-to-body fit for easy layering, its the ideal style for ultimate comfort through the summer and tricky transition seasons.