This Alpha Parka from Arc'teryx is their warmest down belay parka and combines a hybrid insulation of mainly 850 fill goose down with synthetic Coreloft™ insulation in moisture-prone areas. The fabric is seam-taped and combines two types of 2-Layer GORE-TEX® INFINIUM™ fabrics, including extremely lightweight and strong 2-layer GORE-TEX® INFINIUM™ Hadron™ proprietary outer face fabric in high wear areas that is engineered with a liquid crystal polymer ripstop that makes this fabric as abrasion resistant as many other fabrics twice the weight. The GORE-TEX® INFINIUM™ fabrics also block the wind while trapping and holding in more warmth than standard fabrics. Other features include a helmet compatible insulated and adjustable StormHood™, two hand pockets, two internal dump pockets, a zippered chest pocket, full length climbing harness compatible double slider front zipper, and an adjustable hem drawcord. Designed for extremely cold bivouacs and alpine belays.