The Arc'teryx Delta AR Zip is made from lofty high void grid fleece that traps heat and packs down small as an extra layer. The deep cut zip provides venting, trim fit enhances wicking performance and a longer cut keeps snow and rain from sneaking inside. Arc'teryx Delta AR Zip Neck Features: Great warmth to weight ratio Half zip Trim fit for optimal layering Materials: Polartec Thermal Pro High Loft Grid