Kyanite Baselayer Zip Neck WArc'teryx Kyanite Baselayer Zip Neck W Tech Specs The Kyanite Baselayers are made for cold days and mixed output. On the move, the Polartec Power Stretch Pro stretches for outstanding freedom of movement. During rest phases or when it gets really cold the fleece's soft brushed interior traps heat to keep you warm. The fleece's durable nylon outer has a smooth face for comfort under layers, the tall collar extends warmth, and the deep front zipper aids