Mountain Hardwear Super Chockstone Full Zip Jacket - SS16 100% Nylon Double-Weave Fabric - The double-weave fabric is light, stretchy, and offers excellent mobility. Boasting UPF 50 - Blocks out harmful UV rays at altitude. Mock-Style Collar - For extra warmth around the neck. Elastic Cuffs - seals in warmth, blocks out wind. Two Handwarmer Pockets - are harness- and pack-compatible.