WARMCELL Technology-Retains heat close to your body to maintain your optimum temperature. PRIMALOFT GOLD TECHNOLOGY-Primaloft microfibers trap body heat to make this the most thermally-efficient synthetic insulation available. This insulation is enginerred to offer supererior softness, packability, and breathability. International products have separate terms, are sold from abroad and may differ from local products, including fit, age ratings, and language of product, labeling or instructions.