Arc’teryx warmest weight base layer zip neck in the Phase family is appropriate for cold temperatures and high-output activities. Hybrid mapping of Phasic™ SV (in the body) and Phasic™ AR (in underarm area) fabrics in addition to the flatlock construction and comfortable next-to-skin fit eliminates excess bulk and rapidly transfers moisture for efficient evaporation. Ideal for cold days in the alpine, this super-wicking base layer has mid-level insulation to keep you warm and dry, and a zip neck allows for faster venting. Engineered for superior moisture management and rapid dry-times during stop-and-go activities, this form-fitting top keeps the user drier and more comfortable. Encapsulated silver-ion fibres provide durable and long-lasting odour control.