The Acrux AR GTX from Arc'Teryx is the first mountaineering boot to combine the low volume and light weight with the quick dry insulated properties of a double boot. The Acrux AR GTX is the lightest, most durable and slimmest double boot on the market. Fully waterproof construction includes an integrated gaiter and removable Gore Tex liner. Breathable, adaptive fit technology aids overall comfort and cold weather confidence. Removable liners provide insulation options for different conditions and rapid dry times, as well as being a great in tent slipper for cold nights.