Ready your Bora² Mid Backpacking Boot for alpine and winter trips with the Arc'teryx Men's Gore-Tex Insulated Mid Liner. This is basically same Adaptive Fit liner already equipped with Arc'teryx's brand new top-of-the-line footwear, featuring the same foot-hugging comfort with breathable, quick-drying mono-mesh for a truly customized fit. Except this liner is insulated for more comfort in frigid temperatures Arc'teryx slipped Gore-Tex's Performance Comfort Stretch membrane inside the Gore-Tex Low Liner for extremely reliable waterproof, breathable protection. Unlike standard membranes that only provide partial coverage, Performance Comfort Stretch wraps entirely around the foot from top to bottom in order to maximize waterproof, breathable protection. The rubberized bottom lets you stroll around the campsite without your shoes, and it's always smart to have a spare if you have the Bora² Mid Backpacking Boot.